diff --git a/lerna.json b/lerna.json
index 0b60c92ef..46a90aa76 100644
--- a/lerna.json
+++ b/lerna.json
@@ -10,5 +10,5 @@
   "packages": [
     "packages/*"
   ],
-  "version": "0.22.11"
+  "version": "0.23.0"
 }
diff --git a/package.json b/package.json
index 1bb12fbcd..318a1d053 100644
--- a/package.json
+++ b/package.json
@@ -16,6 +16,6 @@
     "test": "jest --coverage"
   },
   "devDependencies": {
-    "@polkadot/dev": "^0.19.25"
+    "@polkadot/dev": "^0.19.28"
   }
 }
diff --git a/packages/util-crypto/package.json b/packages/util-crypto/package.json
index 55088bae4..24814bd2b 100644
--- a/packages/util-crypto/package.json
+++ b/packages/util-crypto/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/util-crypto",
-  "version": "0.22.11",
+  "version": "0.23.0",
   "description": "A collection of useful crypto utilities for @polkadot",
   "main": "index.js",
   "keywords": [
@@ -34,7 +34,7 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.0.0-beta.47",
-    "@polkadot/util": "^0.22.11",
+    "@polkadot/util": "^0.23.0",
     "blakejs": "^1.1.0",
     "js-sha3": "^0.7.0",
     "tweetnacl": "^1.0.0",
diff --git a/packages/util-crypto/src/blake2/asHex.js b/packages/util-crypto/src/blake2/asHex.js
index 73dd38aa6..24e3c2c61 100644
--- a/packages/util-crypto/src/blake2/asHex.js
+++ b/packages/util-crypto/src/blake2/asHex.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const blake2bAsHex = require('./blake2b/asHex');
+import blake2bAsHex from './blake2b/asHex';
 
 /**
   @name blake2AsHex
@@ -16,6 +16,6 @@ const blake2bAsHex = require('./blake2b/asHex');
 
     blake2AsHex('abc') // => 0xba80a53f981c4d0d
 */
-module.exports = function blake2AsHex (data: Uint8Array, bitLength: number = 256): string {
+export default function blake2AsHex (data: Uint8Array, bitLength: number = 256): string {
   return blake2bAsHex(data, bitLength);
-};
+}
diff --git a/packages/util-crypto/src/blake2/asHex.spec.js b/packages/util-crypto/src/blake2/asHex.spec.js
index edf41a354..59e6797c1 100644
--- a/packages/util-crypto/src/blake2/asHex.spec.js
+++ b/packages/util-crypto/src/blake2/asHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const { blake2AsHex } = require('./index');
+import { blake2AsHex } from './index';
 
 describe('blake2AsHex', () => {
   it('returns a 64-bit value (specified)', () => {
diff --git a/packages/util-crypto/src/blake2/asU8a.js b/packages/util-crypto/src/blake2/asU8a.js
index 7c10ed289..8f89ae63b 100644
--- a/packages/util-crypto/src/blake2/asU8a.js
+++ b/packages/util-crypto/src/blake2/asU8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const blake2bAsU8a = require('./blake2b/asU8a');
+import blake2bAsU8a from './blake2b/asU8a';
 
 /**
   @name blake2AsU8a
@@ -16,6 +16,6 @@ const blake2bAsU8a = require('./blake2b/asU8a');
 
     blake2AsU8a('abc') // => [0xba, 0x80, 0xa53, 0xf98, 0x1c, 0x4d, 0x0d]
 */
-module.exports = function blake2AsU8a (data: Uint8Array, bitLength: number = 256, key?: Uint8Array): Uint8Array {
+export default function blake2AsU8a (data: Uint8Array, bitLength: number = 256, key?: Uint8Array): Uint8Array {
   return blake2bAsU8a(data, bitLength, key);
-};
+}
diff --git a/packages/util-crypto/src/blake2/asU8a.spec.js b/packages/util-crypto/src/blake2/asU8a.spec.js
index c45919f7f..78e2c9d1a 100644
--- a/packages/util-crypto/src/blake2/asU8a.spec.js
+++ b/packages/util-crypto/src/blake2/asU8a.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const { blake2AsU8a } = require('./index');
+import { blake2AsU8a } from './index';
 
 describe('blake2AsU8a', () => {
   it('returns a 64-bit value by default', () => {
diff --git a/packages/util-crypto/src/blake2/blake2b/asHex.js b/packages/util-crypto/src/blake2/blake2b/asHex.js
index 3a3817456..b74f167eb 100644
--- a/packages/util-crypto/src/blake2/blake2b/asHex.js
+++ b/packages/util-crypto/src/blake2/blake2b/asHex.js
@@ -3,8 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
-const blake2bAsU8a = require('./asU8a');
+import u8aToHex from '@polkadot/util/u8a/toHex';
+import blake2bAsU8a from './asU8a';
 
 /**
   @name blake2bAsHex
@@ -17,8 +17,8 @@ const blake2bAsU8a = require('./asU8a');
 
     blake2bAsHex('abc') // => '0xba80a53f981c4d0d6a2797b69f12f6e94c212f14685ac4b74b12bb6fdbffa2d17d87c5392aab792dc252d5de4533cc9518d38aa8dbf1925ab92386edd4009923'
 */
-module.exports = function blake2bAsHex (data: Uint8Array, bitLength: number = 512): string {
+export default function blake2bAsHex (data: Uint8Array, bitLength: number = 512): string {
   return u8aToHex(
     blake2bAsU8a(data, bitLength)
   );
-};
+}
diff --git a/packages/util-crypto/src/blake2/blake2b/asHex.spec.js b/packages/util-crypto/src/blake2/blake2b/asHex.spec.js
index 21123e21b..5bfb90793 100644
--- a/packages/util-crypto/src/blake2/blake2b/asHex.spec.js
+++ b/packages/util-crypto/src/blake2/blake2b/asHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const { blake2bAsHex } = require('./index');
+import { blake2bAsHex } from './index';
 
 describe('blake2bAsHex', () => {
   it('creates the correct hash', () => {
diff --git a/packages/util-crypto/src/blake2/blake2b/asU8a.js b/packages/util-crypto/src/blake2/blake2b/asU8a.js
index db597c788..61cef941a 100644
--- a/packages/util-crypto/src/blake2/blake2b/asU8a.js
+++ b/packages/util-crypto/src/blake2/blake2b/asU8a.js
@@ -4,7 +4,7 @@
 // @flow
 
 // TODO: For Node we can also use node-blake2 (npm blake2)
-const blakejs = require('blakejs');
+import blakejs from 'blakejs';
 
 /**
   @name blake2bAsU8a
@@ -17,6 +17,6 @@ const blakejs = require('blakejs');
 
     blake2bAsU8a('abc') // => Uint8Array('508c5e8c327c14e2e1a72ba34eeb452f37458b209ed63a294d999b4c86675982')
 */
-module.exports = function blake2bAsU8a (data: Uint8Array, bitLength: number = 512, key: ?Uint8Array = null): Uint8Array {
+export default function blake2bAsU8a (data: Uint8Array, bitLength: number = 512, key: ?Uint8Array = null): Uint8Array {
   return blakejs.blake2b(data, key, bitLength / 8);
-};
+}
diff --git a/packages/util-crypto/src/blake2/blake2b/asU8a.spec.js b/packages/util-crypto/src/blake2/blake2b/asU8a.spec.js
index b2b754a5d..7ad706626 100644
--- a/packages/util-crypto/src/blake2/blake2b/asU8a.spec.js
+++ b/packages/util-crypto/src/blake2/blake2b/asU8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { blake2bAsU8a } = require('./index');
+import { blake2bAsU8a } from './index';
 
 describe('blake2bAsU8a', () => {
   it('creates the correct hash (default length)', () => {
diff --git a/packages/util-crypto/src/blake2/blake2b/index.js b/packages/util-crypto/src/blake2/blake2b/index.js
index 90476ffc3..4de819f05 100644
--- a/packages/util-crypto/src/blake2/blake2b/index.js
+++ b/packages/util-crypto/src/blake2/blake2b/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const blake2bAsHex = require('./asHex');
-const blake2bAsU8a = require('./asU8a');
+import blake2bAsHex from './asHex';
+import blake2bAsU8a from './asU8a';
 
 /**
   @summary Create [Blake2b](https://blake2.net/) values as hex & Uint8Array output
 */
-module.exports = {
+export {
   blake2bAsHex,
   blake2bAsU8a
 };
diff --git a/packages/util-crypto/src/blake2/index.js b/packages/util-crypto/src/blake2/index.js
index bedaa0422..891a651b4 100644
--- a/packages/util-crypto/src/blake2/index.js
+++ b/packages/util-crypto/src/blake2/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const blake2AsHex = require('./asHex');
-const blake2AsU8a = require('./asU8a');
+import blake2AsHex from './asHex';
+import blake2AsU8a from './asU8a';
 
 /**
   @summary Create blake2b values with specified bitlengths
 */
-module.exports = {
+export {
   blake2AsHex,
   blake2AsU8a
 };
diff --git a/packages/util-crypto/src/index.js b/packages/util-crypto/src/index.js
index 1bb415346..ba11b1fc4 100644
--- a/packages/util-crypto/src/index.js
+++ b/packages/util-crypto/src/index.js
@@ -3,16 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const blake2 = require('./blake2');
-const keccak = require('./keccak');
-const nacl = require('./nacl');
-const random = require('./random');
-const sha512 = require('./sha512');
-const xxhash = require('./xxhash');
-
-/**
-  @summary Utility methods for this package are split into groups
-*/
-module.exports = Object.assign(
-  {}, blake2, keccak, nacl, random, sha512, xxhash
-);
+export * from './blake2';
+export * from './keccak';
+export * from './nacl';
+export * from './random';
+export * from './sha512';
+export * from './xxhash';
diff --git a/packages/util-crypto/src/keccak/asHex.js b/packages/util-crypto/src/keccak/asHex.js
index 61c04e898..dc9546c2a 100644
--- a/packages/util-crypto/src/keccak/asHex.js
+++ b/packages/util-crypto/src/keccak/asHex.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
+import u8aToHex from '@polkadot/util/u8a/toHex';
 
-const keccakAsU8a = require('./asU8a');
+import keccakAsU8a from './asU8a';
 
 /**
   @name keccakAsHex
@@ -18,8 +18,8 @@ const keccakAsU8a = require('./asU8a');
 
     keccakAsHex('123') // => 0x...
 */
-module.exports = function keccakAsHex (value: Buffer | Uint8Array | string): string {
+export default function keccakAsHex (value: Buffer | Uint8Array | string): string {
   return u8aToHex(
     keccakAsU8a(value)
   );
-};
+}
diff --git a/packages/util-crypto/src/keccak/asHex.spec.js b/packages/util-crypto/src/keccak/asHex.spec.js
index 370aab0f9..301f579c4 100644
--- a/packages/util-crypto/src/keccak/asHex.spec.js
+++ b/packages/util-crypto/src/keccak/asHex.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { keccakAsHex } = require('./index');
+import { keccakAsHex } from './index';
 
 const value = 'test value';
 const result = '2d07364b5c231c56ce63d49430e085ea3033c750688ba532b24029124c26ca5e';
diff --git a/packages/util-crypto/src/keccak/asU8a.js b/packages/util-crypto/src/keccak/asU8a.js
index da2ffd706..f5b0cc192 100644
--- a/packages/util-crypto/src/keccak/asU8a.js
+++ b/packages/util-crypto/src/keccak/asU8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const { keccak256 } = require('js-sha3');
+import { keccak256 } from 'js-sha3';
 
 /**
   @name keccakAsU8a
@@ -16,8 +16,8 @@ const { keccak256 } = require('js-sha3');
 
     keccakAsU8a('123') // => Uint8Array
 */
-module.exports = function keccakAsU8a (value: Buffer | Uint8Array | string): Uint8Array {
+export default function keccakAsU8a (value: Buffer | Uint8Array | string): Uint8Array {
   return new Uint8Array(
     keccak256.arrayBuffer(value)
   );
-};
+}
diff --git a/packages/util-crypto/src/keccak/asU8a.spec.js b/packages/util-crypto/src/keccak/asU8a.spec.js
index e2d450553..87b871166 100644
--- a/packages/util-crypto/src/keccak/asU8a.spec.js
+++ b/packages/util-crypto/src/keccak/asU8a.spec.js
@@ -2,10 +2,10 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import hexToU8a from '@polkadot/util/hex/toU8a';
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const { keccakAsU8a } = require('./index');
+import { keccakAsU8a } from './index';
 
 describe('keccakAsU8a', () => {
   const input = 'test value';
diff --git a/packages/util-crypto/src/keccak/index.js b/packages/util-crypto/src/keccak/index.js
index 2c3f4b2c2..5f1744c93 100644
--- a/packages/util-crypto/src/keccak/index.js
+++ b/packages/util-crypto/src/keccak/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const keccakAsHex = require('./asHex');
-const keccakAsU8a = require('./asU8a');
+import keccakAsHex from './asHex';
+import keccakAsU8a from './asU8a';
 
 /**
   @summary Create Keccak256 values as hex & Uint8Array output
 */
-module.exports = {
+export {
   keccakAsHex,
   keccakAsU8a
 };
diff --git a/packages/util-crypto/src/nacl/decrypt.js b/packages/util-crypto/src/nacl/decrypt.js
index 748dbfc98..ec544f03b 100644
--- a/packages/util-crypto/src/nacl/decrypt.js
+++ b/packages/util-crypto/src/nacl/decrypt.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name naclDecrypt
@@ -16,6 +16,6 @@ const nacl = require('tweetnacl');
 
     naclDecrypt([...], [...], [...]) // => [...]
 */
-module.exports = function naclDecrypt (encrypted: Uint8Array, nonce: Uint8Array, secret: Uint8Array): ?Uint8Array {
+export default function naclDecrypt (encrypted: Uint8Array, nonce: Uint8Array, secret: Uint8Array): ?Uint8Array {
   return nacl.secretbox.open(encrypted, nonce, secret);
-};
+}
diff --git a/packages/util-crypto/src/nacl/decrypt.spec.js b/packages/util-crypto/src/nacl/decrypt.spec.js
index 49715e508..af8e2801f 100644
--- a/packages/util-crypto/src/nacl/decrypt.spec.js
+++ b/packages/util-crypto/src/nacl/decrypt.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { naclDecrypt, naclEncrypt } = require('./index');
+import { naclDecrypt, naclEncrypt } from './index';
 
 describe('naclDecrypt', () => {
   it('decrypts a encrypted message', () => {
diff --git a/packages/util-crypto/src/nacl/encrypt.js b/packages/util-crypto/src/nacl/encrypt.js
index 4a25c5067..577d51951 100644
--- a/packages/util-crypto/src/nacl/encrypt.js
+++ b/packages/util-crypto/src/nacl/encrypt.js
@@ -3,15 +3,15 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
+import nacl from 'tweetnacl';
+
+import randomAsU8a from '../random/asU8a';
+
 type Encrypted = {
   encrypted: Uint8Array,
   nonce: Uint8Array
 };
 
-const nacl = require('tweetnacl');
-
-const randomAsU8a = require('../random/asU8a');
-
 /**
   @name naclEncrypt
   @signature naclEncrypt (message: Uint8Array, secret: Uint8Array, nonce?: Uint8Array): { encrypted: Uint8Array, nonce: Uint8Array }
@@ -23,9 +23,9 @@ const randomAsU8a = require('../random/asU8a');
 
     naclSign([...], [...]) // => [...]
 */
-module.exports = function naclEncrypt (message: Uint8Array, secret: Uint8Array, nonce: Uint8Array = randomAsU8a(24)): Encrypted {
+export default function naclEncrypt (message: Uint8Array, secret: Uint8Array, nonce: Uint8Array = randomAsU8a(24)): Encrypted {
   return {
     encrypted: nacl.secretbox(message, nonce, secret),
     nonce
   };
-};
+}
diff --git a/packages/util-crypto/src/nacl/encrypt.spec.js b/packages/util-crypto/src/nacl/encrypt.spec.js
index 28acb4f4f..d62ddfda9 100644
--- a/packages/util-crypto/src/nacl/encrypt.spec.js
+++ b/packages/util-crypto/src/nacl/encrypt.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { naclEncrypt } = require('./index');
+import { naclEncrypt } from './index';
 
 describe('naclEncrypt', () => {
   it('encrypts a message', () => {
diff --git a/packages/util-crypto/src/nacl/index.js b/packages/util-crypto/src/nacl/index.js
index da8f23aaa..aeaac062b 100644
--- a/packages/util-crypto/src/nacl/index.js
+++ b/packages/util-crypto/src/nacl/index.js
@@ -3,19 +3,19 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const naclDecrypt = require('./decrypt');
-const naclEncrypt = require('./encrypt');
-const naclKeypairFromRandom = require('./keypair/fromRandom');
-const naclKeypairFromSecret = require('./keypair/fromSecret');
-const naclKeypairFromSeed = require('./keypair/fromSeed');
-const naclKeypairFromString = require('./keypair/fromString');
-const naclSign = require('./sign');
-const naclVerify = require('./verify');
+import naclDecrypt from './decrypt';
+import naclEncrypt from './encrypt';
+import naclKeypairFromRandom from './keypair/fromRandom';
+import naclKeypairFromSecret from './keypair/fromSecret';
+import naclKeypairFromSeed from './keypair/fromSeed';
+import naclKeypairFromString from './keypair/fromString';
+import naclSign from './sign';
+import naclVerify from './verify';
 
 /**
   @summary Implements [NaCl](http://nacl.cr.yp.to/) secret-key authenticated encryption, public-key authenticated encryption, hashing, and public-key signatures
 */
-module.exports = {
+export {
   naclDecrypt,
   naclEncrypt,
   naclKeypairFromRandom,
diff --git a/packages/util-crypto/src/nacl/keypair/fromRandom.js b/packages/util-crypto/src/nacl/keypair/fromRandom.js
index 84be602c5..714d80931 100644
--- a/packages/util-crypto/src/nacl/keypair/fromRandom.js
+++ b/packages/util-crypto/src/nacl/keypair/fromRandom.js
@@ -5,7 +5,7 @@
 
 import type { KeypairType } from '../../types';
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name naclKeypair
@@ -18,6 +18,6 @@ const nacl = require('tweetnacl');
 
     naclKeypair() // => { secretKey: [...], publicKey: [...] }
 */
-module.exports = function naclKeypairFromRandom (): KeypairType {
+export default function naclKeypairFromRandom (): KeypairType {
   return nacl.sign.keyPair();
-};
+}
diff --git a/packages/util-crypto/src/nacl/keypair/fromRandom.spec.js b/packages/util-crypto/src/nacl/keypair/fromRandom.spec.js
index 22b37d724..bf0814837 100644
--- a/packages/util-crypto/src/nacl/keypair/fromRandom.spec.js
+++ b/packages/util-crypto/src/nacl/keypair/fromRandom.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { naclKeypairFromRandom } = require('../index');
+import { naclKeypairFromRandom } from '../index';
 
 describe('naclKeypairFromRandom', () => {
   let keypair;
diff --git a/packages/util-crypto/src/nacl/keypair/fromSecret.js b/packages/util-crypto/src/nacl/keypair/fromSecret.js
index 470f1ba17..795b968a2 100644
--- a/packages/util-crypto/src/nacl/keypair/fromSecret.js
+++ b/packages/util-crypto/src/nacl/keypair/fromSecret.js
@@ -5,7 +5,7 @@
 
 import type { KeypairType } from '../../types';
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name naclKeypairFromSecret
@@ -18,6 +18,6 @@ const nacl = require('tweetnacl');
 
     naclKeypairFromSecret(...) // => { secretKey: [...], publicKey: [...] }
 */
-module.exports = function naclKeypairFromSecret (secret: Uint8Array): KeypairType {
+export default function naclKeypairFromSecret (secret: Uint8Array): KeypairType {
   return nacl.sign.keyPair.fromSecretKey(secret);
-};
+}
diff --git a/packages/util-crypto/src/nacl/keypair/fromSecret.spec.js b/packages/util-crypto/src/nacl/keypair/fromSecret.spec.js
index c6a539ca5..a5c7b8e47 100644
--- a/packages/util-crypto/src/nacl/keypair/fromSecret.spec.js
+++ b/packages/util-crypto/src/nacl/keypair/fromSecret.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { naclKeypairFromSecret } = require('../index');
+import { naclKeypairFromSecret } from '../index';
 
 describe('naclKeypairFromSecret', () => {
   const secretKey = new Uint8Array([
diff --git a/packages/util-crypto/src/nacl/keypair/fromSeed.js b/packages/util-crypto/src/nacl/keypair/fromSeed.js
index d8f67e179..92c61ef6c 100644
--- a/packages/util-crypto/src/nacl/keypair/fromSeed.js
+++ b/packages/util-crypto/src/nacl/keypair/fromSeed.js
@@ -5,7 +5,7 @@
 
 import type { KeypairType } from '../../types';
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name naclKeypairFromSeed
@@ -18,6 +18,6 @@ const nacl = require('tweetnacl');
 
     naclKeypairFromSeed(...) // => { secretKey: [...], publicKey: [...] }
 */
-module.exports = function naclKeypairFromSeed (seed: Uint8Array): KeypairType {
+export default function naclKeypairFromSeed (seed: Uint8Array): KeypairType {
   return nacl.sign.keyPair.fromSeed(seed);
-};
+}
diff --git a/packages/util-crypto/src/nacl/keypair/fromSeed.spec.js b/packages/util-crypto/src/nacl/keypair/fromSeed.spec.js
index 87b8826d8..1e9fceec4 100644
--- a/packages/util-crypto/src/nacl/keypair/fromSeed.spec.js
+++ b/packages/util-crypto/src/nacl/keypair/fromSeed.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const { naclKeypairFromSeed } = require('../index');
+import { naclKeypairFromSeed } from '../index';
 
 describe('naclKeypairFromSeed', () => {
   // NOTE: Aligned with Rust test, b"12345678901234567890123456789012"
diff --git a/packages/util-crypto/src/nacl/keypair/fromString.js b/packages/util-crypto/src/nacl/keypair/fromString.js
index 150ee5529..7927eca57 100644
--- a/packages/util-crypto/src/nacl/keypair/fromString.js
+++ b/packages/util-crypto/src/nacl/keypair/fromString.js
@@ -5,10 +5,10 @@
 
 import type { KeypairType } from '../../types';
 
-const u8aFromUtf8 = require('@polkadot/util/u8a/fromUtf8');
+import u8aFromUtf8 from '@polkadot/util/u8a/fromUtf8';
 
-const blake2AsU8a = require('../../blake2/asU8a');
-const fromSeed = require('./fromSeed');
+import blake2AsU8a from '../../blake2/asU8a';
+import fromSeed from './fromSeed';
 
 /**
   @name naclKeypairFromString
@@ -21,11 +21,11 @@ const fromSeed = require('./fromSeed');
 
     naclKeypairFromString('test') // => { secretKey: [...], publicKey: [...] }
 */
-module.exports = function naclKeypairFromString (value: string): KeypairType {
+export default function naclKeypairFromString (value: string): KeypairType {
   return fromSeed(
     blake2AsU8a(
       u8aFromUtf8(value),
       256
     )
   );
-};
+}
diff --git a/packages/util-crypto/src/nacl/keypair/fromString.spec.js b/packages/util-crypto/src/nacl/keypair/fromString.spec.js
index d8fcb7a13..5c8a030d2 100644
--- a/packages/util-crypto/src/nacl/keypair/fromString.spec.js
+++ b/packages/util-crypto/src/nacl/keypair/fromString.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { naclKeypairFromString } = require('../index');
+import { naclKeypairFromString } from '../index';
 
 describe('naclKeypairFromSeed', () => {
   it('generates a valid publicKey/secretKey pair', () => {
diff --git a/packages/util-crypto/src/nacl/sign.js b/packages/util-crypto/src/nacl/sign.js
index 2b35f9afe..d80b9b8fd 100644
--- a/packages/util-crypto/src/nacl/sign.js
+++ b/packages/util-crypto/src/nacl/sign.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name naclSign
@@ -16,6 +16,6 @@ const nacl = require('tweetnacl');
 
     naclSign([...], [...]) // => [...]
 */
-module.exports = function naclSign (message: Uint8Array, secretKey: Uint8Array): Uint8Array {
+export default function naclSign (message: Uint8Array, secretKey: Uint8Array): Uint8Array {
   return nacl.sign.detached(message, secretKey);
-};
+}
diff --git a/packages/util-crypto/src/nacl/sign.spec.js b/packages/util-crypto/src/nacl/sign.spec.js
index 4738a935c..64e922d2a 100644
--- a/packages/util-crypto/src/nacl/sign.spec.js
+++ b/packages/util-crypto/src/nacl/sign.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const { naclSign, naclKeypairFromSeed } = require('./index');
+import { naclSign, naclKeypairFromSeed } from './index';
 
 describe('naclSign', () => {
   let secretKey;
diff --git a/packages/util-crypto/src/nacl/verify.js b/packages/util-crypto/src/nacl/verify.js
index aa2bb979c..4ef985a71 100644
--- a/packages/util-crypto/src/nacl/verify.js
+++ b/packages/util-crypto/src/nacl/verify.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name naclSign
@@ -16,6 +16,6 @@ const nacl = require('tweetnacl');
 
     naclVerify([...], [...], [...]) // => true/false
 */
-module.exports = function naclVerify (message: Uint8Array, signature: Uint8Array, publicKey: Uint8Array): boolean {
+export default function naclVerify (message: Uint8Array, signature: Uint8Array, publicKey: Uint8Array): boolean {
   return nacl.sign.detached.verify(message, signature, publicKey);
-};
+}
diff --git a/packages/util-crypto/src/nacl/verify.spec.js b/packages/util-crypto/src/nacl/verify.spec.js
index 1abfb617c..6362fbcda 100644
--- a/packages/util-crypto/src/nacl/verify.spec.js
+++ b/packages/util-crypto/src/nacl/verify.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const { naclVerify, naclKeypairFromSeed } = require('./index');
+import { naclVerify, naclKeypairFromSeed } from './index';
 
 describe('naclSign', () => {
   let publicKey;
diff --git a/packages/util-crypto/src/random/asHex.js b/packages/util-crypto/src/random/asHex.js
index 437e3591d..d6a667c92 100644
--- a/packages/util-crypto/src/random/asHex.js
+++ b/packages/util-crypto/src/random/asHex.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
+import u8aToHex from '@polkadot/util/u8a/toHex';
 
-const randomAsU8a = require('./asU8a');
+import randomAsU8a from './asU8a';
 
 /**
   @name randomAsHex
@@ -18,8 +18,8 @@ const randomAsU8a = require('./asU8a');
 
     randomAsHex() // => 0x...
 */
-module.exports = function randomAsHex (length?: number = 32): string {
+export default function randomAsHex (length?: number = 32): string {
   return u8aToHex(
     randomAsU8a(length)
   );
-};
+}
diff --git a/packages/util-crypto/src/random/asHex.spec.js b/packages/util-crypto/src/random/asHex.spec.js
index 976aeeeb5..306110869 100644
--- a/packages/util-crypto/src/random/asHex.spec.js
+++ b/packages/util-crypto/src/random/asHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isHex = require('@polkadot/util/is/hex');
+import isHex from '@polkadot/util/is/hex';
 
-const { randomAsHex } = require('./index');
+import { randomAsHex } from './index';
 
 describe('randomAsBuffer', () => {
   it('generated results does not match', () => {
diff --git a/packages/util-crypto/src/random/asNumber.js b/packages/util-crypto/src/random/asNumber.js
index 5ac12f576..ebaff60a4 100644
--- a/packages/util-crypto/src/random/asNumber.js
+++ b/packages/util-crypto/src/random/asNumber.js
@@ -3,10 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexToBn = require('@polkadot/util/hex/toBn');
-const BN = require('bn.js');
+import BN from 'bn.js';
+import hexToBn from '@polkadot/util/hex/toBn';
 
-const randomAsHex = require('./asHex');
+import randomAsHex from './asHex';
 
 const BN_53 = new BN(0b11111111111111111111111111111111111111111111111111111);
 
@@ -21,8 +21,8 @@ const BN_53 = new BN(0b11111111111111111111111111111111111111111111111111111);
 
     randomAsNumber() // => <random number>
 */
-module.exports = function randomAsNumber (): number {
+export default function randomAsNumber (): number {
   return hexToBn(
     randomAsHex(8)
   ).and(BN_53).toNumber();
-};
+}
diff --git a/packages/util-crypto/src/random/asNumber.spec.js b/packages/util-crypto/src/random/asNumber.spec.js
index e7a677307..d7a7a9c2e 100644
--- a/packages/util-crypto/src/random/asNumber.spec.js
+++ b/packages/util-crypto/src/random/asNumber.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { randomAsNumber } = require('./index');
+import { randomAsNumber } from './index';
 
 describe('randomAsNumber', () => {
   it('generates subsequent non-matching numbers', () => {
diff --git a/packages/util-crypto/src/random/asU8a.js b/packages/util-crypto/src/random/asU8a.js
index cf7106641..c93325681 100644
--- a/packages/util-crypto/src/random/asU8a.js
+++ b/packages/util-crypto/src/random/asU8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name randomAsU8a
@@ -16,6 +16,6 @@ const nacl = require('tweetnacl');
 
     randomAsU8s() // => Uint8Array([...])
 */
-module.exports = function randomAsU8a (length?: number = 32): Uint8Array {
+export default function randomAsU8a (length?: number = 32): Uint8Array {
   return nacl.randomBytes(length);
-};
+}
diff --git a/packages/util-crypto/src/random/asU8a.spec.js b/packages/util-crypto/src/random/asU8a.spec.js
index b2ee07bf5..88d9ffb62 100644
--- a/packages/util-crypto/src/random/asU8a.spec.js
+++ b/packages/util-crypto/src/random/asU8a.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isU8a = require('@polkadot/util/is/u8a');
+import isU8a from '@polkadot/util/is/u8a';
 
-const { randomAsU8a } = require('./index');
+import { randomAsU8a } from './index';
 
 describe('randomAsU8a', () => {
   it('generates a Uint8Array', () => {
diff --git a/packages/util-crypto/src/random/index.js b/packages/util-crypto/src/random/index.js
index 493431fb2..1e91c4e5a 100644
--- a/packages/util-crypto/src/random/index.js
+++ b/packages/util-crypto/src/random/index.js
@@ -3,14 +3,14 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const randomAsHex = require('./asHex');
-const randomAsNumber = require('./asNumber');
-const randomAsU8a = require('./asU8a');
+import randomAsHex from './asHex';
+import randomAsNumber from './asNumber';
+import randomAsU8a from './asU8a';
 
 /**
   @summary Returns a sequence of secure random bytes in a variety of formats
 */
-module.exports = {
+export {
   randomAsHex,
   randomAsNumber,
   randomAsU8a
diff --git a/packages/util-crypto/src/sha512/asU8a.js b/packages/util-crypto/src/sha512/asU8a.js
index a16d9d551..c13d04692 100644
--- a/packages/util-crypto/src/sha512/asU8a.js
+++ b/packages/util-crypto/src/sha512/asU8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const nacl = require('tweetnacl');
+import nacl from 'tweetnacl';
 
 /**
   @name sha512AsU8a
@@ -16,6 +16,6 @@ const nacl = require('tweetnacl');
 
     sha512AsU8a(Uint8Array.from([...])) // => Uint8Array([...])
 */
-module.exports = function sha512AsU8a (data: Uint8Array): Uint8Array {
+export default function sha512AsU8a (data: Uint8Array): Uint8Array {
   return nacl.hash(data);
-};
+}
diff --git a/packages/util-crypto/src/sha512/asU8a.spec.js b/packages/util-crypto/src/sha512/asU8a.spec.js
index f9d4a8878..6bf9b5ba1 100644
--- a/packages/util-crypto/src/sha512/asU8a.spec.js
+++ b/packages/util-crypto/src/sha512/asU8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { sha512AsU8a } = require('./index');
+import { sha512AsU8a } from './index';
 
 describe('sha512AsU8a', () => {
   it('creates a sha-512 hash', () => {
diff --git a/packages/util-crypto/src/sha512/index.js b/packages/util-crypto/src/sha512/index.js
index 3318c9037..b3ac7917f 100644
--- a/packages/util-crypto/src/sha512/index.js
+++ b/packages/util-crypto/src/sha512/index.js
@@ -3,11 +3,11 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const sha512AsU8a = require('./asU8a');
+import sha512AsU8a from './asU8a';
 
 /**
   @summary Implements Sha-512 hashing functions for a variety of input and outputs
 */
-module.exports = {
+export {
   sha512AsU8a
 };
diff --git a/packages/util-crypto/src/xxhash/asHex.js b/packages/util-crypto/src/xxhash/asHex.js
index e42e4dc24..0b0bb99e1 100644
--- a/packages/util-crypto/src/xxhash/asHex.js
+++ b/packages/util-crypto/src/xxhash/asHex.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
+import u8aToHex from '@polkadot/util/u8a/toHex';
 
-const xxhashAsU8a = require('./asU8a');
+import xxhashAsU8a from './asU8a';
 
 /**
   @name xxhashAsHex
@@ -18,8 +18,8 @@ const xxhashAsU8a = require('./asU8a');
 
     xxhashAsHex('abc') // => 0x44bc2cf5ad770999
 */
-module.exports = function xxhashAsHex (data: Buffer | Uint8Array | string, bitLength: number = 64): string {
+export default function xxhashAsHex (data: Buffer | Uint8Array | string, bitLength: number = 64): string {
   return u8aToHex(
     xxhashAsU8a(data, bitLength)
   );
-};
+}
diff --git a/packages/util-crypto/src/xxhash/asHex.spec.js b/packages/util-crypto/src/xxhash/asHex.spec.js
index 42fc19cfc..f7661294b 100644
--- a/packages/util-crypto/src/xxhash/asHex.spec.js
+++ b/packages/util-crypto/src/xxhash/asHex.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { xxhashAsHex } = require('./index');
+import { xxhashAsHex } from './index';
 
 describe('xxhashAsHex', () => {
   it('returns a 64-bit value by default', () => {
diff --git a/packages/util-crypto/src/xxhash/asU8a.js b/packages/util-crypto/src/xxhash/asU8a.js
index ebddad78c..9b5e14434 100644
--- a/packages/util-crypto/src/xxhash/asU8a.js
+++ b/packages/util-crypto/src/xxhash/asU8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const xxhash64AsBn = require('./xxhash64/asBn');
+import xxhash64AsBn from './xxhash64/asBn';
 
 /**
   @name xxhashAsU8a
@@ -16,7 +16,7 @@ const xxhash64AsBn = require('./xxhash64/asBn');
 
     xxhashAsU8a('abc') // => 0x44bc2cf5ad770999
 */
-module.exports = function xxhashAsU8a (data: Buffer | Uint8Array | string, bitLength: number = 64): Uint8Array {
+export default function xxhashAsU8a (data: Buffer | Uint8Array | string, bitLength: number = 64): Uint8Array {
   const byteLength = Math.ceil(bitLength / 8);
   const iterations = Math.ceil(bitLength / 64);
   const u8a = new Uint8Array(byteLength);
@@ -26,4 +26,4 @@ module.exports = function xxhashAsU8a (data: Buffer | Uint8Array | string, bitLe
   }
 
   return u8a;
-};
+}
diff --git a/packages/util-crypto/src/xxhash/asU8a.spec.js b/packages/util-crypto/src/xxhash/asU8a.spec.js
index 2850bd609..4a7e1d6ec 100644
--- a/packages/util-crypto/src/xxhash/asU8a.spec.js
+++ b/packages/util-crypto/src/xxhash/asU8a.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const { xxhashAsU8a } = require('./index');
+import { xxhashAsU8a } from './index';
 
 describe('xxhashAsU8a', () => {
   it('returns a 64-bit value by default', () => {
diff --git a/packages/util-crypto/src/xxhash/index.js b/packages/util-crypto/src/xxhash/index.js
index ecf64ea01..7216701d1 100644
--- a/packages/util-crypto/src/xxhash/index.js
+++ b/packages/util-crypto/src/xxhash/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const xxhashAsHex = require('./asHex');
-const xxhashAsU8a = require('./asU8a');
+import xxhashAsHex from './asHex';
+import xxhashAsU8a from './asU8a';
 
 /**
   @summary Create xxhash64 values with specified bitlengths
 */
-module.exports = {
+export {
   xxhashAsHex,
   xxhashAsU8a
 };
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asBn.js b/packages/util-crypto/src/xxhash/xxhash64/asBn.js
index 91f65df33..78e87bbe7 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asBn.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asBn.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const xxhash64AsRaw = require('./asRaw');
+import xxhash64AsRaw from './asRaw';
 
 /**
   @name xxhash64AsBn
@@ -18,9 +18,9 @@ const xxhash64AsRaw = require('./asRaw');
 
     xxhash64AsBn('abcd', 0xabcd)) // => new BN(0xe29f70f8b8c96df7)
 */
-module.exports = function xxhash64AsBn (data: Buffer | Uint8Array | string, seed: number): BN {
+export default function xxhash64AsBn (data: Buffer | Uint8Array | string, seed: number): BN {
   return new BN(
     xxhash64AsRaw(data, seed),
     16
   );
-};
+}
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asBn.spec.js b/packages/util-crypto/src/xxhash/xxhash64/asBn.spec.js
index 92154cc50..82b6bb407 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asBn.spec.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asBn.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { xxhash64AsBn } = require('./index');
+import { xxhash64AsBn } from './index';
 
 describe('xxhash64AsBn', () => {
   it('creates the correct BN output', () => {
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asHex.js b/packages/util-crypto/src/xxhash/xxhash64/asHex.js
index 7e5785bd1..c4ab3377f 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asHex.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asHex.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexAddPrefix = require('@polkadot/util/hex/addPrefix');
+import hexAddPrefix from '@polkadot/util/hex/addPrefix';
 
-const xxhash64AsRaw = require('./asRaw');
+import xxhash64AsRaw from './asRaw';
 
 /**
   @name xxhash64AsHex
@@ -18,8 +18,8 @@ const xxhash64AsRaw = require('./asRaw');
 
     xxhash64AsHex('abcd', 0xabcd)) // => 0xe29f70f8b8c96df7
 */
-module.exports = function xxhash64AsHex (data: Buffer | Uint8Array | string, seed: number): string {
+export default function xxhash64AsHex (data: Buffer | Uint8Array | string, seed: number): string {
   return hexAddPrefix(
     xxhash64AsRaw(data, seed)
   );
-};
+}
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asHex.spec.js b/packages/util-crypto/src/xxhash/xxhash64/asHex.spec.js
index 48c1f81b3..203189a32 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asHex.spec.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asHex.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { xxhash64AsHex } = require('./index');
+import { xxhash64AsHex } from './index';
 
 describe('xxhash64AsHex', () => {
   it('creates the correct hex output', () => {
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asRaw.js b/packages/util-crypto/src/xxhash/xxhash64/asRaw.js
index 3570faf43..0ebcea008 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asRaw.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asRaw.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const xxhash64AsValue = require('./asValue');
+import xxhash64AsValue from './asValue';
 
 /**
   @name xxhash64AsRaw
@@ -16,6 +16,6 @@ const xxhash64AsValue = require('./asValue');
 
     xxhash64AsRaw('abcd', 0xabcd)) // => e29f70f8b8c96df7
 */
-module.exports = function xxhash64AsRaw (data: Buffer | Uint8Array | string, seed: number): string {
+export default function xxhash64AsRaw (data: Buffer | Uint8Array | string, seed: number): string {
   return xxhash64AsValue(data, seed).toString(16);
-};
+}
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asRaw.spec.js b/packages/util-crypto/src/xxhash/xxhash64/asRaw.spec.js
index 41982a820..382b3a52b 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asRaw.spec.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asRaw.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { xxhash64AsRaw } = require('./index');
+import { xxhash64AsRaw } from './index';
 
 describe('xxhash64AsRaw', () => {
   it('creates the correct non-prefixed hex output', () => {
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asValue.js b/packages/util-crypto/src/xxhash/xxhash64/asValue.js
index 815a7daa3..7d74637b8 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asValue.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asValue.js
@@ -5,21 +5,20 @@
 
 import type { xxhashjs$Result } from 'xxhashjs';
 
-const isBuffer = require('@polkadot/util/is/buffer');
-const isString = require('@polkadot/util/is/string');
-const u8aToBuffer = require('@polkadot/util/u8a/toBuffer');
-const xxhashjs = require('xxhashjs');
+import isBuffer from '@polkadot/util/is/buffer';
+import isString from '@polkadot/util/is/string';
+import u8aToBuffer from '@polkadot/util/u8a/toBuffer';
+import xxhashjs from 'xxhashjs';
 
-module.exports = function xxhash64AsValue (data: Buffer | Uint8Array | string, seed: number): xxhashjs$Result {
+export default function xxhash64AsValue (data: Buffer | Uint8Array | string, seed: number): xxhashjs$Result {
   if (isBuffer(data) || isString(data)) {
     // $FlowFixMe we have determined the type
     return xxhashjs.h64(data, seed);
   }
 
   return xxhashjs.h64(
-    // NOTE: We can't use data.buffer, it has the incorrect length
     // $FlowFixMe we have determined the type
     u8aToBuffer(data),
     seed
   );
-};
+}
diff --git a/packages/util-crypto/src/xxhash/xxhash64/asValue.spec.js b/packages/util-crypto/src/xxhash/xxhash64/asValue.spec.js
index 6beba115b..84c82f44d 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/asValue.spec.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/asValue.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const xxhash64AsValue = require('./asValue');
+import xxhash64AsValue from './asValue';
 
 describe('xxhash64AsValue', () => {
   it('creates the correct output (string input)', () => {
diff --git a/packages/util-crypto/src/xxhash/xxhash64/index.js b/packages/util-crypto/src/xxhash/xxhash64/index.js
index 425bda44e..41b8c3eec 100644
--- a/packages/util-crypto/src/xxhash/xxhash64/index.js
+++ b/packages/util-crypto/src/xxhash/xxhash64/index.js
@@ -3,14 +3,14 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const xxhash64AsBn = require('./asBn');
-const xxhash64AsHex = require('./asHex');
-const xxhash64AsRaw = require('./asRaw');
+import xxhash64AsBn from './asBn';
+import xxhash64AsHex from './asHex';
+import xxhash64AsRaw from './asRaw';
 
 /**
   @summary Create [XXHash](http://cyan4973.github.io/xxHash/) values as BN, hex & number output
 */
-module.exports = {
+export {
   xxhash64AsBn,
   xxhash64AsHex,
   xxhash64AsRaw
diff --git a/packages/util-keyring/package.json b/packages/util-keyring/package.json
index 16020561b..933fe4616 100644
--- a/packages/util-keyring/package.json
+++ b/packages/util-keyring/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/util-keyring",
-  "version": "0.22.11",
+  "version": "0.23.0",
   "description": "Keyring management",
   "main": "index.js",
   "engines": {
@@ -36,8 +36,8 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.0.0-beta.47",
-    "@polkadot/util": "^0.22.11",
-    "@polkadot/util-crypto": "^0.22.11",
+    "@polkadot/util": "^0.23.0",
+    "@polkadot/util-crypto": "^0.23.0",
     "bs58": "^4.0.1"
   }
 }
diff --git a/packages/util-keyring/src/address/decode.js b/packages/util-keyring/src/address/decode.js
index 4e78f528d..c9e0ec7f0 100644
--- a/packages/util-keyring/src/address/decode.js
+++ b/packages/util-keyring/src/address/decode.js
@@ -5,15 +5,16 @@
 
 // Original implementation: https://github.com/paritytech/polka-ui/blob/4858c094684769080f5811f32b081dd7780b0880/src/polkadot.js#L6
 
-const bs58 = require('bs58');
-const assert = require('@polkadot/util/assert');
-const bufferToU8a = require('@polkadot/util/buffer/toU8a');
-const isHex = require('@polkadot/util/is/hex');
-const isU8a = require('@polkadot/util/is/u8a');
-const u8aToU8a = require('@polkadot/util/u8a/toU8a');
-const blake2b = require('@polkadot/util-crypto/blake2/asU8a');
+import bs58 from 'bs58';
 
-module.exports = function decode (encoded: string | Uint8Array): Uint8Array {
+import assert from '@polkadot/util/assert';
+import bufferToU8a from '@polkadot/util/buffer/toU8a';
+import isHex from '@polkadot/util/is/hex';
+import isU8a from '@polkadot/util/is/u8a';
+import u8aToU8a from '@polkadot/util/u8a/toU8a';
+import blake2b from '@polkadot/util-crypto/blake2/asU8a';
+
+export default function decode (encoded: string | Uint8Array): Uint8Array {
   if (isU8a(encoded) || isHex(encoded)) {
     return u8aToU8a(encoded);
   }
@@ -32,4 +33,4 @@ module.exports = function decode (encoded: string | Uint8Array): Uint8Array {
   assert(decoded[33] === hash[0] && decoded[34] === hash[1], error(' Invalid decoded address checksum'));
 
   return decoded.slice(1, 33);
-};
+}
diff --git a/packages/util-keyring/src/address/decode.spec.js b/packages/util-keyring/src/address/decode.spec.js
index d36129be8..3875810e2 100644
--- a/packages/util-keyring/src/address/decode.spec.js
+++ b/packages/util-keyring/src/address/decode.spec.js
@@ -3,8 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const keyring = require('../testingPairs')();
-const decode = require('./decode');
+import testingPairs from '../testingPairs';
+import decode from './decode';
+
+const keyring = testingPairs();
 
 describe('decode', () => {
   it('decodes an address', () => {
diff --git a/packages/util-keyring/src/address/encode.js b/packages/util-keyring/src/address/encode.js
index f0467fb68..06cd68b14 100644
--- a/packages/util-keyring/src/address/encode.js
+++ b/packages/util-keyring/src/address/encode.js
@@ -5,16 +5,17 @@
 
 // Original implementation: https://github.com/paritytech/polka-ui/blob/4858c094684769080f5811f32b081dd7780b0880/src/polkadot.js#L34
 
-const bs58 = require('bs58');
-const assert = require('@polkadot/util/assert');
-const u8aConcat = require('@polkadot/util/u8a/concat');
-const u8aToBuffer = require('@polkadot/util/u8a/toBuffer');
-const u8aToU8a = require('@polkadot/util/u8a/toU8a');
-const blake2b = require('@polkadot/util-crypto/blake2/asU8a');
+import bs58 from 'bs58';
+
+import assert from '@polkadot/util/assert';
+import u8aConcat from '@polkadot/util/u8a/concat';
+import u8aToBuffer from '@polkadot/util/u8a/toBuffer';
+import u8aToU8a from '@polkadot/util/u8a/toU8a';
+import blake2b from '@polkadot/util-crypto/blake2/asU8a';
 
 const PREFIX = new Uint8Array([42]);
 
-module.exports = function encode (_publicKey: Uint8Array | string): string {
+export default function encode (_publicKey: Uint8Array | string): string {
   const publicKey = u8aToU8a(_publicKey);
 
   assert(publicKey.length === 32, `Expected a valid publicKey to convert`);
@@ -27,4 +28,4 @@ module.exports = function encode (_publicKey: Uint8Array | string): string {
       u8aConcat(input, hash.subarray(0, 2))
     )
   );
-};
+}
diff --git a/packages/util-keyring/src/address/encode.spec.js b/packages/util-keyring/src/address/encode.spec.js
index 764a8ffd0..0a98aade6 100644
--- a/packages/util-keyring/src/address/encode.spec.js
+++ b/packages/util-keyring/src/address/encode.spec.js
@@ -3,8 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const keyring = require('../testingPairs')();
-const encode = require('./encode');
+import testingPairs from '../testingPairs';
+import encode from './encode';
+
+const keyring = testingPairs();
 
 describe('encode', () => {
   it('encodes an address to a valid value', () => {
diff --git a/packages/util-keyring/src/address/index.js b/packages/util-keyring/src/address/index.js
index 5659f3f28..5b18118fc 100644
--- a/packages/util-keyring/src/address/index.js
+++ b/packages/util-keyring/src/address/index.js
@@ -3,10 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const decodeAddress = require('./decode');
-const encodeAddress = require('./encode');
+import decodeAddress from './decode';
+import encodeAddress from './encode';
 
-module.exports = {
+export {
   decodeAddress,
   encodeAddress
 };
diff --git a/packages/util-keyring/src/index.js b/packages/util-keyring/src/index.js
index a57715463..efdd1a2e4 100644
--- a/packages/util-keyring/src/index.js
+++ b/packages/util-keyring/src/index.js
@@ -5,14 +5,14 @@
 
 import type { KeyringInstance, KeyringPair, KeyringPair$Json, KeyringPair$Meta } from './types';
 
-const naclKeypairFromSeed = require('@polkadot/util-crypto/nacl/keypair/fromSeed');
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import naclKeypairFromSeed from '@polkadot/util-crypto/nacl/keypair/fromSeed';
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const addressDecode = require('./address/decode');
-const createPair = require('./pair');
-const createPairs = require('./pairs');
+import addressDecode from './address/decode';
+import createPair from './pair';
+import createPairs from './pairs';
 
-module.exports = function keyring (): KeyringInstance {
+export default function keyring (): KeyringInstance {
   const pairs = createPairs();
   const addFromAddress = (address: string | Uint8Array, meta?: KeyringPair$Meta, defaultEncoded?: Uint8Array) =>
     pairs.add(createPair({ publicKey: addressDecode(address) }, meta, defaultEncoded));
@@ -33,4 +33,4 @@ module.exports = function keyring (): KeyringInstance {
     toJson: (address: string | Uint8Array, passphrase?: string): KeyringPair$Json =>
       pairs.get(address).toJson(passphrase)
   };
-};
+}
diff --git a/packages/util-keyring/src/index.spec.js b/packages/util-keyring/src/index.spec.js
index 2d4ad37c9..90a984ce2 100644
--- a/packages/util-keyring/src/index.spec.js
+++ b/packages/util-keyring/src/index.spec.js
@@ -2,10 +2,10 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import hexToU8a from '@polkadot/util/hex/toU8a';
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const index = require('./index');
+import index from './index';
 
 describe('keypair', () => {
   const publicKeyOne = new Uint8Array([47, 140, 97, 41, 216, 22, 207, 81, 195, 116, 188, 127, 8, 195, 230, 62, 209, 86, 207, 120, 174, 251, 74, 101, 80, 217, 123, 135, 153, 121, 119, 238]);
diff --git a/packages/util-keyring/src/pair/decode.js b/packages/util-keyring/src/pair/decode.js
index e6c4c12b2..19b51cad0 100644
--- a/packages/util-keyring/src/pair/decode.js
+++ b/packages/util-keyring/src/pair/decode.js
@@ -3,21 +3,21 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aConcat = require('@polkadot/util/u8a/concat');
-const u8aFixLength = require('@polkadot/util/u8a/fixLength');
-const u8aFromString = require('@polkadot/util/u8a/fromString');
-const assert = require('@polkadot/util/assert');
-const naclDecrypt = require('@polkadot/util-crypto/nacl/decrypt');
-const naclFromSeed = require('@polkadot/util-crypto/nacl/keypair/fromSeed');
+import u8aConcat from '@polkadot/util/u8a/concat';
+import u8aFixLength from '@polkadot/util/u8a/fixLength';
+import u8aFromString from '@polkadot/util/u8a/fromString';
+import assert from '@polkadot/util/assert';
+import naclDecrypt from '@polkadot/util-crypto/nacl/decrypt';
+import naclFromSeed from '@polkadot/util-crypto/nacl/keypair/fromSeed';
 
-const { PKCS8_DIVIDER, PKCS8_HEADER } = require('./defaults');
+import { PKCS8_DIVIDER, PKCS8_HEADER } from './defaults';
 
 const KEY_LENGTH = 32;
 const SEED_OFFSET = PKCS8_HEADER.length;
 const DIV_OFFSET = SEED_OFFSET + KEY_LENGTH;
 const PUBLIC_OFFSET = SEED_OFFSET + KEY_LENGTH + PKCS8_DIVIDER.length;
 
-module.exports = function decode (passphrase?: string, _encrypted?: Uint8Array) {
+export default function decode (passphrase?: string, _encrypted?: Uint8Array) {
   assert(_encrypted, `No encrypted data available to decode`);
 
   // flowlint-next-line unclear-type:off
@@ -47,4 +47,4 @@ module.exports = function decode (passphrase?: string, _encrypted?: Uint8Array)
     publicKey,
     secretKey
   };
-};
+}
diff --git a/packages/util-keyring/src/pair/decode.spec.js b/packages/util-keyring/src/pair/decode.spec.js
index 7c6184823..4ea5a1194 100644
--- a/packages/util-keyring/src/pair/decode.spec.js
+++ b/packages/util-keyring/src/pair/decode.spec.js
@@ -2,7 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const keyring = require('../testingPairs')();
+import testingPairs from '../testingPairs';
+
+const keyring = testingPairs();
 
 describe('decode', () => {
   it('fails when no data provided', () => {
diff --git a/packages/util-keyring/src/pair/defaults.js b/packages/util-keyring/src/pair/defaults.js
index 09436ee7d..71d9a8030 100644
--- a/packages/util-keyring/src/pair/defaults.js
+++ b/packages/util-keyring/src/pair/defaults.js
@@ -6,7 +6,7 @@
 const PKCS8_DIVIDER = new Uint8Array([161, 35, 3, 33, 0]);
 const PKCS8_HEADER = new Uint8Array([48, 83, 2, 1, 1, 48, 5, 6, 3, 43, 101, 112, 4, 34, 4, 32]);
 
-module.exports = {
+export {
   PKCS8_DIVIDER,
   PKCS8_HEADER
 };
diff --git a/packages/util-keyring/src/pair/encode.js b/packages/util-keyring/src/pair/encode.js
index b85e6fdb3..c9c95336a 100644
--- a/packages/util-keyring/src/pair/encode.js
+++ b/packages/util-keyring/src/pair/encode.js
@@ -3,14 +3,14 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aConcat = require('@polkadot/util/u8a/concat');
-const u8aFixLength = require('@polkadot/util/u8a/fixLength');
-const u8aFromString = require('@polkadot/util/u8a/fromString');
-const naclEncrypt = require('@polkadot/util-crypto/nacl/encrypt');
+import u8aConcat from '@polkadot/util/u8a/concat';
+import u8aFixLength from '@polkadot/util/u8a/fixLength';
+import u8aFromString from '@polkadot/util/u8a/fromString';
+import naclEncrypt from '@polkadot/util-crypto/nacl/encrypt';
 
-const { PKCS8_DIVIDER, PKCS8_HEADER } = require('./defaults');
+import { PKCS8_DIVIDER, PKCS8_HEADER } from './defaults';
 
-module.exports = function encode (secretKey: Uint8Array, passphrase?: string): Uint8Array {
+export default function encode (secretKey: Uint8Array, passphrase?: string): Uint8Array {
   const encoded = u8aConcat(
     PKCS8_HEADER,
     secretKey.subarray(0, 32),
@@ -26,4 +26,4 @@ module.exports = function encode (secretKey: Uint8Array, passphrase?: string): U
   const { encrypted, nonce } = naclEncrypt(encoded, u8aFixLength(u8aFromString(passphrase), 256, true));
 
   return u8aConcat(nonce, encrypted);
-};
+}
diff --git a/packages/util-keyring/src/pair/encode.spec.js b/packages/util-keyring/src/pair/encode.spec.js
index 53488cf8a..fee935379 100644
--- a/packages/util-keyring/src/pair/encode.spec.js
+++ b/packages/util-keyring/src/pair/encode.spec.js
@@ -2,12 +2,14 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const keyring = require('../testingPairs')();
-const { PKCS8_DIVIDER, PKCS8_HEADER } = require('./defaults');
+import testingPairs from '../testingPairs';
+import { PKCS8_DIVIDER, PKCS8_HEADER } from './defaults';
 
 const PKCS8_LENGTH = PKCS8_DIVIDER.length + PKCS8_HEADER.length + 64;
 const ENCODED_LENGTH = 125;
 
+const keyring = testingPairs();
+
 describe('encode', () => {
   it('returns PKCS8 when no passphrase supplied', () => {
     expect(
diff --git a/packages/util-keyring/src/pair/getMeta.js b/packages/util-keyring/src/pair/getMeta.js
index d3ce6787c..e51e04c62 100644
--- a/packages/util-keyring/src/pair/getMeta.js
+++ b/packages/util-keyring/src/pair/getMeta.js
@@ -6,6 +6,6 @@
 import type { KeyringPair$Meta } from '../types';
 import type { PairState } from './types';
 
-module.exports = function getMeta (state: PairState): KeyringPair$Meta {
+export default function getMeta (state: PairState): KeyringPair$Meta {
   return state.meta;
-};
+}
diff --git a/packages/util-keyring/src/pair/index.js b/packages/util-keyring/src/pair/index.js
index 5af898834..6235cad5e 100644
--- a/packages/util-keyring/src/pair/index.js
+++ b/packages/util-keyring/src/pair/index.js
@@ -7,17 +7,17 @@ import type { KeypairType } from '@polkadot/util-crypto/types';
 import type { KeyringPair, KeyringPair$Json, KeyringPair$Meta } from '../types';
 import type { PairState } from './types';
 
-const naclSign = require('@polkadot/util-crypto/nacl/sign');
-const naclVerify = require('@polkadot/util-crypto/nacl/verify');
+import naclSign from '@polkadot/util-crypto/nacl/sign';
+import naclVerify from '@polkadot/util-crypto/nacl/verify';
 
-const encodeAddress = require('../address/encode');
-const decode = require('./decode');
-const encode = require('./encode');
-const getMeta = require('./getMeta');
-const setMeta = require('./setMeta');
-const toJson = require('./toJson');
+import encodeAddress from '../address/encode';
+import decode from './decode';
+import encode from './encode';
+import getMeta from './getMeta';
+import setMeta from './setMeta';
+import toJson from './toJson';
 
-module.exports = function pair ({ publicKey, secretKey }: $Shape<KeypairType>, meta?: KeyringPair$Meta = {}, defaultEncoded?: Uint8Array): KeyringPair {
+export default function pair ({ publicKey, secretKey }: $Shape<KeypairType>, meta?: KeyringPair$Meta = {}, defaultEncoded?: Uint8Array): KeyringPair {
   const state: PairState = {
     address: encodeAddress(publicKey),
     meta: { ...meta }
@@ -50,4 +50,4 @@ module.exports = function pair ({ publicKey, secretKey }: $Shape<KeypairType>, m
     verify: (message: Uint8Array, signature: Uint8Array): boolean =>
       naclVerify(message, signature, publicKey)
   };
-};
+}
diff --git a/packages/util-keyring/src/pair/index.spec.js b/packages/util-keyring/src/pair/index.spec.js
index 3363ced11..997f585b9 100644
--- a/packages/util-keyring/src/pair/index.spec.js
+++ b/packages/util-keyring/src/pair/index.spec.js
@@ -2,7 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const keyring = require('../testingPairs')();
+import testingPairs from '../testingPairs';
+
+const keyring = testingPairs();
 
 // aligned with @polkadot/util-crypto tests
 describe('pair', () => {
diff --git a/packages/util-keyring/src/pair/nobody.js b/packages/util-keyring/src/pair/nobody.js
index 498acb9bb..6c03e0f8e 100644
--- a/packages/util-keyring/src/pair/nobody.js
+++ b/packages/util-keyring/src/pair/nobody.js
@@ -5,7 +5,7 @@
 
 import type { KeyringPair, KeyringPair$Json, KeyringPair$Meta } from '../types';
 
-const addressEncode = require('../address/encode');
+import addressEncode from '../address/encode';
 
 const publicKey = new Uint8Array(32);
 const address = addressEncode(publicKey);
@@ -23,7 +23,7 @@ const json = {
   meta
 };
 
-module.exports = function everybody (): KeyringPair {
+export default function everybody (): KeyringPair {
   return {
     address: (): string =>
       address,
@@ -46,4 +46,4 @@ module.exports = function everybody (): KeyringPair {
     verify: (message: Uint8Array, signature: Uint8Array): boolean =>
       false
   };
-};
+}
diff --git a/packages/util-keyring/src/pair/setMeta.js b/packages/util-keyring/src/pair/setMeta.js
index 15f47c4ba..ca6185f2f 100644
--- a/packages/util-keyring/src/pair/setMeta.js
+++ b/packages/util-keyring/src/pair/setMeta.js
@@ -6,9 +6,9 @@
 import type { KeyringPair$Meta } from '../types';
 import type { PairState } from './types';
 
-module.exports = function setMeta (state: PairState, meta: KeyringPair$Meta): void {
+export default function setMeta (state: PairState, meta: KeyringPair$Meta): void {
   state.meta = {
     ...state.meta,
     ...meta
   };
-};
+}
diff --git a/packages/util-keyring/src/pair/toJson.js b/packages/util-keyring/src/pair/toJson.js
index 8b0c42ecc..d80e4ac7d 100644
--- a/packages/util-keyring/src/pair/toJson.js
+++ b/packages/util-keyring/src/pair/toJson.js
@@ -6,9 +6,9 @@
 import type { KeyringPair$Json } from '../types';
 import type { PairState } from './types';
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
+import u8aToHex from '@polkadot/util/u8a/toHex';
 
-module.exports = function toJson ({ address, meta }: PairState, encoded: Uint8Array, isEncrypted: boolean): KeyringPair$Json {
+export default function toJson ({ address, meta }: PairState, encoded: Uint8Array, isEncrypted: boolean): KeyringPair$Json {
   return {
     address,
     encoded: u8aToHex(encoded),
@@ -23,4 +23,4 @@ module.exports = function toJson ({ address, meta }: PairState, encoded: Uint8Ar
       ...meta
     }
   };
-};
+}
diff --git a/packages/util-keyring/src/pair/toJson.spec.js b/packages/util-keyring/src/pair/toJson.spec.js
index 63d1cb415..bf77b08d2 100644
--- a/packages/util-keyring/src/pair/toJson.spec.js
+++ b/packages/util-keyring/src/pair/toJson.spec.js
@@ -2,7 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const keyring = require('../testingPairs')();
+import testingPairs from '../testingPairs';
+
+const keyring = testingPairs();
 
 describe('toJson', () => {
   it('creates an unencoded output with no passphrase', () => {
diff --git a/packages/util-keyring/src/pairs.js b/packages/util-keyring/src/pairs.js
index e665814fb..45cb51691 100644
--- a/packages/util-keyring/src/pairs.js
+++ b/packages/util-keyring/src/pairs.js
@@ -5,19 +5,19 @@
 
 import type { KeyringPairs, KeyringPair } from './types';
 
+import assert from '@polkadot/util/assert';
+import isHex from '@polkadot/util/is/hex';
+import isU8a from '@polkadot/util/is/u8a';
+import u8aToHex from '@polkadot/util/u8a/toHex';
+import u8aToU8a from '@polkadot/util/u8a/toU8a';
+
+import addressDecode from './address/decode';
+
 type KeyringPairMap = {
   [Uint8Array]: KeyringPair
 };
 
-const assert = require('@polkadot/util/assert');
-const isHex = require('@polkadot/util/is/hex');
-const isU8a = require('@polkadot/util/is/u8a');
-const u8aToHex = require('@polkadot/util/u8a/toHex');
-const u8aToU8a = require('@polkadot/util/u8a/toU8a');
-
-const addressDecode = require('./address/decode');
-
-module.exports = function pairs (): KeyringPairs {
+export default function pairs (): KeyringPairs {
   const self: KeyringPairMap = {};
 
   return {
@@ -47,4 +47,4 @@ module.exports = function pairs (): KeyringPairs {
       delete self[addressDecode(address)];
     }
   };
-};
+}
diff --git a/packages/util-keyring/src/testing.js b/packages/util-keyring/src/testing.js
index 6c1e0caf5..8cc1e8d86 100644
--- a/packages/util-keyring/src/testing.js
+++ b/packages/util-keyring/src/testing.js
@@ -5,10 +5,10 @@
 
 import type { KeyringInstance } from './types';
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import hexToU8a from '@polkadot/util/hex/toU8a';
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const createKeyring = require('./index');
+import createKeyring from './index';
 
 function padSeed (seed: string): Uint8Array {
   return u8aFromString(seed.padEnd(32, ' '));
@@ -33,7 +33,7 @@ const SEEDS = {
     hexToU8a('0x9d61b19deffd5a60ba844af492ec2cc44449c5697b326919703bac031cae7f60')
 };
 
-module.exports = function testKeyring (): KeyringInstance {
+export default function testKeyring (): KeyringInstance {
   const keyring = createKeyring();
 
   Object
@@ -46,4 +46,4 @@ module.exports = function testKeyring (): KeyringInstance {
     });
 
   return keyring;
-};
+}
diff --git a/packages/util-keyring/src/testingPairs.js b/packages/util-keyring/src/testingPairs.js
index 6c3280f5f..da8ca8413 100644
--- a/packages/util-keyring/src/testingPairs.js
+++ b/packages/util-keyring/src/testingPairs.js
@@ -5,15 +5,15 @@
 
 import type { KeyringPair, KeyringInstance } from './types';
 
+import createKeyring from './testing';
+import nobody from './pair/nobody';
+
 type TestKeyringMap = {
   _keyring: KeyringInstance,
   [string]: KeyringPair
 };
 
-const createKeyring = require('./testing');
-const nobody = require('./pair/nobody')();
-
-module.exports = function testKeyringPairs (): TestKeyringMap {
+export default function testKeyringPairs (): TestKeyringMap {
   const keyring = createKeyring();
   const pairs = keyring.getPairs();
 
@@ -23,5 +23,5 @@ module.exports = function testKeyringPairs (): TestKeyringMap {
     result[(name: string)] = pair;
 
     return result;
-  }, { _keyring: keyring, nobody });
-};
+  }, { _keyring: keyring, nobody: nobody() });
+}
diff --git a/packages/util-rlp/package.json b/packages/util-rlp/package.json
index 0dd7d2802..9ebf8e04a 100644
--- a/packages/util-rlp/package.json
+++ b/packages/util-rlp/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/util-rlp",
-  "version": "0.22.11",
+  "version": "0.23.0",
   "description": "RLP encoding and decoding",
   "main": "index.js",
   "keywords": [
@@ -34,7 +34,7 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.0.0-beta.47",
-    "@polkadot/util": "^0.22.11"
+    "@polkadot/util": "^0.23.0"
   },
   "devDependencies": {
     "ethereumjs-testing": "^1.0.4"
diff --git a/packages/util-rlp/src/decode.js b/packages/util-rlp/src/decode.js
index 876b344b8..3989837ca 100644
--- a/packages/util-rlp/src/decode.js
+++ b/packages/util-rlp/src/decode.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const decoder = require('./decoder');
+import decoder from './decoder';
 
 /**
   @name decode
@@ -16,4 +16,4 @@ const decoder = require('./decoder');
 
     encode(new Uint8Array([0x83, 0x64, 0x6f, 0x67])) // => 'dog' as Uint8Array
 */
-module.exports = decoder;
+export default decoder;
diff --git a/packages/util-rlp/src/decode.spec.js b/packages/util-rlp/src/decode.spec.js
index 311595aaf..aab13584f 100644
--- a/packages/util-rlp/src/decode.spec.js
+++ b/packages/util-rlp/src/decode.spec.js
@@ -2,12 +2,14 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
-const u8aToHex = require('@polkadot/util/u8a/toHex');
+import hexToU8a from '@polkadot/util/hex/toU8a';
+import u8aToHex from '@polkadot/util/u8a/toHex';
 
-const { decode, encode } = require('./index');
+import { decode, encode } from './index';
 
-const rlptests = require('../test/getTests')('RLPTests/rlptest.json');
+import getTests from '../test/getTests';
+
+const rlptests = getTests('RLPTests/rlptest.json');
 
 describe('decode', () => {
   it('returns empty list for undefined inputs', () => {
diff --git a/packages/util-rlp/src/decoder/decode.js b/packages/util-rlp/src/decoder/decode.js
index 4d666b1b3..9ef1222d7 100644
--- a/packages/util-rlp/src/decoder/decode.js
+++ b/packages/util-rlp/src/decoder/decode.js
@@ -5,17 +5,17 @@
 
 import type { DecodeFunc, DecodeOutput } from './types';
 
+import decodeListLong from './listLong';
+import decodeListShort from './listShort';
+import decodeNumber from './number';
+import decodeSingle from './single';
+import decodeString from './string';
+
 type Decoder = {
   max: number,
   fn: (decode: DecodeFunc, input: Uint8Array) => DecodeOutput
 };
 
-const decodeListLong = require('./listLong');
-const decodeListShort = require('./listShort');
-const decodeNumber = require('./number');
-const decodeSingle = require('./single');
-const decodeString = require('./string');
-
 const decoders: Array<Decoder> = [
   { max: 0x7f, fn: decodeSingle },
   { max: 0xb7, fn: decodeString },
@@ -24,11 +24,9 @@ const decoders: Array<Decoder> = [
   { max: 0xff, fn: decodeListLong }
 ];
 
-function decode (input: Uint8Array): DecodeOutput {
+export default function decode (input: Uint8Array): DecodeOutput {
   return decoders
     .find(({ max }) => input[0] <= max)
     // $FlowFixMe last entry (listLong) is max uint8 value
     .fn(decode, input);
 }
-
-module.exports = decode;
diff --git a/packages/util-rlp/src/decoder/index.js b/packages/util-rlp/src/decoder/index.js
index 89d811613..56d2e74b9 100644
--- a/packages/util-rlp/src/decoder/index.js
+++ b/packages/util-rlp/src/decoder/index.js
@@ -3,12 +3,12 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const assert = require('@polkadot/util/assert');
+import assert from '@polkadot/util/assert';
 
-const internalDecode = require('./decode');
+import internalDecode from './decode';
 
 // flowlint-next-line unclear-type:off
-module.exports = function decoder (input?: Uint8Array): Uint8Array | Array<any> {
+export default function decoder (input?: Uint8Array): Uint8Array | Array<any> {
   if (!input || input.length === 0) {
     return new Uint8Array([]);
   }
@@ -18,4 +18,4 @@ module.exports = function decoder (input?: Uint8Array): Uint8Array | Array<any>
   assert(remainder.length === 0, 'invalid remainder');
 
   return decoded;
-};
+}
diff --git a/packages/util-rlp/src/decoder/listLong.js b/packages/util-rlp/src/decoder/listLong.js
index 44a350fd8..d1b015d53 100644
--- a/packages/util-rlp/src/decoder/listLong.js
+++ b/packages/util-rlp/src/decoder/listLong.js
@@ -5,11 +5,11 @@
 
 import type { DecodeFunc, DecodeOutput } from './types';
 
-const assert = require('@polkadot/util/assert');
+import assert from '@polkadot/util/assert';
 
-const safeParseInt = require('./safeParseInt');
+import safeParseInt from './safeParseInt';
 
-module.exports = function decodeListLong (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+export default function decodeListLong (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
   const llength = input[0] - 0xf6;
   const length = safeParseInt(input.slice(1, llength));
   const totalLength = llength + length;
@@ -32,4 +32,4 @@ module.exports = function decodeListLong (decode: DecodeFunc, input: Uint8Array)
     decoded,
     remainder: input.slice(totalLength)
   };
-};
+}
diff --git a/packages/util-rlp/src/decoder/listShort.js b/packages/util-rlp/src/decoder/listShort.js
index 8ef7f481d..c02f12179 100644
--- a/packages/util-rlp/src/decoder/listShort.js
+++ b/packages/util-rlp/src/decoder/listShort.js
@@ -5,7 +5,7 @@
 
 import type { DecodeFunc, DecodeOutput } from './types';
 
-module.exports = function decodeListShort (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+export default function decodeListShort (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
   const length = input[0] - 0xbf;
   let innerRemainder = input.slice(1, length);
   const decoded = [];
@@ -21,4 +21,4 @@ module.exports = function decodeListShort (decode: DecodeFunc, input: Uint8Array
     decoded,
     remainder: input.slice(length)
   };
-};
+}
diff --git a/packages/util-rlp/src/decoder/number.js b/packages/util-rlp/src/decoder/number.js
index 3984d9e62..c1911ca29 100644
--- a/packages/util-rlp/src/decoder/number.js
+++ b/packages/util-rlp/src/decoder/number.js
@@ -5,11 +5,11 @@
 
 import type { DecodeFunc, DecodeOutput } from './types';
 
-const assert = require('@polkadot/util/assert');
+import assert from '@polkadot/util/assert';
 
-const safeParseInt = require('./safeParseInt');
+import safeParseInt from './safeParseInt';
 
-module.exports = function decodeNumber (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+export default function decodeNumber (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
   const llength = input[0] - 0xb6;
   const length = safeParseInt(input.slice(1, llength));
   const decoded = input.slice(llength, length + llength);
@@ -20,4 +20,4 @@ module.exports = function decodeNumber (decode: DecodeFunc, input: Uint8Array):
     decoded,
     remainder: input.slice(length + llength)
   };
-};
+}
diff --git a/packages/util-rlp/src/decoder/safeParseInt.js b/packages/util-rlp/src/decoder/safeParseInt.js
index 607b7c5e4..abfb52e70 100644
--- a/packages/util-rlp/src/decoder/safeParseInt.js
+++ b/packages/util-rlp/src/decoder/safeParseInt.js
@@ -3,10 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const assert = require('@polkadot/util/assert');
+import assert from '@polkadot/util/assert';
 
-module.exports = function safeParseInt (input: Uint8Array): number {
+export default function safeParseInt (input: Uint8Array): number {
   assert(input[0] > 0, 'invalid RLP: extra zeros');
 
   return input.reduce((result, value) => (result * 256) + value, 0);
-};
+}
diff --git a/packages/util-rlp/src/decoder/safeParseInt.spec.js b/packages/util-rlp/src/decoder/safeParseInt.spec.js
index cfe39f6c9..500bd6585 100644
--- a/packages/util-rlp/src/decoder/safeParseInt.spec.js
+++ b/packages/util-rlp/src/decoder/safeParseInt.spec.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const safeParseInt = require('./safeParseInt');
+import safeParseInt from './safeParseInt';
 
 describe('safeParseInt', () => {
   it('does not allow 0 in first position', () => {
diff --git a/packages/util-rlp/src/decoder/single.js b/packages/util-rlp/src/decoder/single.js
index 7d73b3f08..ad9bade99 100644
--- a/packages/util-rlp/src/decoder/single.js
+++ b/packages/util-rlp/src/decoder/single.js
@@ -5,9 +5,9 @@
 
 import type { DecodeFunc, DecodeOutput } from './types';
 
-module.exports = function decodeSingle (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+export default function decodeSingle (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
   return {
     decoded: input.slice(0, 1),
     remainder: input.slice(1)
   };
-};
+}
diff --git a/packages/util-rlp/src/decoder/string.js b/packages/util-rlp/src/decoder/string.js
index 377628aaa..caf1666f1 100644
--- a/packages/util-rlp/src/decoder/string.js
+++ b/packages/util-rlp/src/decoder/string.js
@@ -5,9 +5,9 @@
 
 import type { DecodeFunc, DecodeOutput } from './types';
 
-const assert = require('@polkadot/util/assert');
+import assert from '@polkadot/util/assert';
 
-module.exports = function decodeString (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+export default function decodeString (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
   const firstByte = input[0];
   const length = firstByte - 0x7f;
   let decoded;
@@ -25,4 +25,4 @@ module.exports = function decodeString (decode: DecodeFunc, input: Uint8Array):
     decoded,
     remainder: input.slice(length)
   };
-};
+}
diff --git a/packages/util-rlp/src/encode.js b/packages/util-rlp/src/encode.js
index 8e5224b75..5fb1b9cf8 100644
--- a/packages/util-rlp/src/encode.js
+++ b/packages/util-rlp/src/encode.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const encoder = require('./encoder');
+import encoder from './encoder';
 
 /**
   @name encode
@@ -16,4 +16,4 @@ const encoder = require('./encoder');
 
     encode('dog') // => [0x83, 0x64, 0x6f, 0x67]
 */
-module.exports = encoder;
+export default encoder;
diff --git a/packages/util-rlp/src/encode.spec.js b/packages/util-rlp/src/encode.spec.js
index 67d858c93..54f12fa97 100644
--- a/packages/util-rlp/src/encode.spec.js
+++ b/packages/util-rlp/src/encode.spec.js
@@ -2,11 +2,13 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
+import u8aToHex from '@polkadot/util/u8a/toHex';
 
-const { encode } = require('./index');
+import { encode } from './index';
 
-const rlptests = require('../test/getTests')('RLPTests/rlptest.json');
+import getTests from '../test/getTests';
+
+const rlptests = getTests('RLPTests/rlptest.json');
 
 describe('encode', () => {
   rlptests.forEach(({ name, input, output }) => {
diff --git a/packages/util-rlp/src/encoder/array.js b/packages/util-rlp/src/encoder/array.js
index 1e8f86355..661e783f4 100644
--- a/packages/util-rlp/src/encoder/array.js
+++ b/packages/util-rlp/src/encoder/array.js
@@ -5,16 +5,16 @@
 
 import type { EncodeFunc } from './types';
 
-const u8aConcat = require('@polkadot/util/u8a/concat');
+import u8aConcat from '@polkadot/util/u8a/concat';
 
-const encodeLength = require('./length');
+import encodeLength from './length';
 
 // flowlint-next-line unclear-type:off
-module.exports = function encodeArray (encoder: EncodeFunc, input: any): Uint8Array {
+export default function encodeArray (encoder: EncodeFunc, input: any): Uint8Array {
   const encoded = u8aConcat.apply(null, input.map(encoder));
 
   return u8aConcat(
     encodeLength(encoded.length, 192),
     encoded
   );
-};
+}
diff --git a/packages/util-rlp/src/encoder/index.js b/packages/util-rlp/src/encoder/index.js
index be94eef5a..7d838ee4f 100644
--- a/packages/util-rlp/src/encoder/index.js
+++ b/packages/util-rlp/src/encoder/index.js
@@ -3,17 +3,15 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const encodeArray = require('./array');
-const toU8a = require('./toU8a');
-const encodeU8a = require('./u8a');
+import encodeArray from './array';
+import toU8a from './toU8a';
+import encodeU8a from './u8a';
 
 // flowlint-next-line unclear-type:off
-function encoder (input: any): Uint8Array {
+export default function encoder (input: any): Uint8Array {
   if (input instanceof Array) {
     return encodeArray(encoder, input);
   }
 
   return encodeU8a(encoder, toU8a(input));
 }
-
-module.exports = encoder;
diff --git a/packages/util-rlp/src/encoder/length.js b/packages/util-rlp/src/encoder/length.js
index e5d82d995..ae3e1e907 100644
--- a/packages/util-rlp/src/encoder/length.js
+++ b/packages/util-rlp/src/encoder/length.js
@@ -3,10 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const numberToHex = require('@polkadot/util/number/toHex');
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import numberToHex from '@polkadot/util/number/toHex';
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-module.exports = function encodeLength (length: number, offset: number): Uint8Array {
+export default function encodeLength (length: number, offset: number): Uint8Array {
   if (length < 56) {
     return new Uint8Array([length + offset]);
   }
@@ -16,4 +16,4 @@ module.exports = function encodeLength (length: number, offset: number): Uint8Ar
   return hexToU8a(
     numberToHex(offset + 55 + hexLength.length / 2) + hexLength
   );
-};
+}
diff --git a/packages/util-rlp/src/encoder/length.spec.js b/packages/util-rlp/src/encoder/length.spec.js
index 2a4ab2f44..b5ea0b9d8 100644
--- a/packages/util-rlp/src/encoder/length.spec.js
+++ b/packages/util-rlp/src/encoder/length.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const encodeLength = require('./length');
+import encodeLength from './length';
 
 describe('encodeLength', () => {
   it('returns offset + length where <= 55', () => {
diff --git a/packages/util-rlp/src/encoder/toU8a.js b/packages/util-rlp/src/encoder/toU8a.js
index bffc5b51c..1f5da0c60 100644
--- a/packages/util-rlp/src/encoder/toU8a.js
+++ b/packages/util-rlp/src/encoder/toU8a.js
@@ -3,6 +3,21 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
+import assert from '@polkadot/util/assert';
+import bnToU8a from '@polkadot/util/bn/toU8a';
+import bufferToU8a from '@polkadot/util/buffer/toU8a';
+import hexHasPrefix from '@polkadot/util/hex/hasPrefix';
+import hexToU8a from '@polkadot/util/hex/toU8a';
+import isBn from '@polkadot/util/is/bn';
+import isBuffer from '@polkadot/util/is/buffer';
+import isNull from '@polkadot/util/is/null';
+import isNumber from '@polkadot/util/is/number';
+import isString from '@polkadot/util/is/string';
+import isU8a from '@polkadot/util/is/u8a';
+import isUndefined from '@polkadot/util/is/undefined';
+import numberToU8a from '@polkadot/util/number/toU8a';
+import u8aFromUtf8 from '@polkadot/util/u8a/fromUtf8';
+
 type Encoder = {
   // flowlint-next-line unclear-type:off
   check: (value: any) => boolean,
@@ -10,21 +25,6 @@ type Encoder = {
   fn: (value: any) => Uint8Array
 };
 
-const assert = require('@polkadot/util/assert');
-const bnToU8a = require('@polkadot/util/bn/toU8a');
-const bufferToU8a = require('@polkadot/util/buffer/toU8a');
-const hexHasPrefix = require('@polkadot/util/hex/hasPrefix');
-const hexToU8a = require('@polkadot/util/hex/toU8a');
-const isBn = require('@polkadot/util/is/bn');
-const isBuffer = require('@polkadot/util/is/buffer');
-const isNull = require('@polkadot/util/is/null');
-const isNumber = require('@polkadot/util/is/number');
-const isString = require('@polkadot/util/is/string');
-const isU8a = require('@polkadot/util/is/u8a');
-const isUndefined = require('@polkadot/util/is/undefined');
-const numberToU8a = require('@polkadot/util/number/toU8a');
-const u8aFromUtf8 = require('@polkadot/util/u8a/fromUtf8');
-
 function newEmpty (): Uint8Array {
   return new Uint8Array([]);
 }
@@ -53,11 +53,11 @@ const encoders: Array<Encoder> = [
 ];
 
 // flowlint-next-line unclear-type:off
-module.exports = function toU8a (value: any): Uint8Array {
+export default function toU8a (value: any): Uint8Array {
   const encoder = encoders.find(({ check }) => check(value));
 
   assert(encoder, 'invalid type');
 
   // $FlowFixMe value checked above
   return encoder.fn(value);
-};
+}
diff --git a/packages/util-rlp/src/encoder/toU8a.spec.js b/packages/util-rlp/src/encoder/toU8a.spec.js
index 52012142b..023b4e82c 100644
--- a/packages/util-rlp/src/encoder/toU8a.spec.js
+++ b/packages/util-rlp/src/encoder/toU8a.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const toU8a = require('./toU8a');
+import toU8a from './toU8a';
 
 describe('toU8a', () => {
   it('returns a Uint8Array input as-is', () => {
diff --git a/packages/util-rlp/src/encoder/u8a.js b/packages/util-rlp/src/encoder/u8a.js
index e09fbd103..88cc302ca 100644
--- a/packages/util-rlp/src/encoder/u8a.js
+++ b/packages/util-rlp/src/encoder/u8a.js
@@ -5,11 +5,11 @@
 
 import type { EncodeFunc } from './types';
 
-const u8aConcat = require('@polkadot/util/u8a/concat');
+import u8aConcat from '@polkadot/util/u8a/concat';
 
-const encodeLength = require('./length');
+import encodeLength from './length';
 
-module.exports = function encodeU8a (encoder: EncodeFunc, input: Uint8Array): Uint8Array {
+export default function encodeU8a (encoder: EncodeFunc, input: Uint8Array): Uint8Array {
   if (input.length === 1 && input[0] < 128) {
     return input;
   }
@@ -18,4 +18,4 @@ module.exports = function encodeU8a (encoder: EncodeFunc, input: Uint8Array): Ui
     encodeLength(input.length, 128),
     input
   );
-};
+}
diff --git a/packages/util-rlp/src/index.js b/packages/util-rlp/src/index.js
index f661193f6..85c654cad 100644
--- a/packages/util-rlp/src/index.js
+++ b/packages/util-rlp/src/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const decode = require('./decode');
-const encode = require('./encode');
+import decode from './decode';
+import encode from './encode';
 
 /**
   @summary Utility methods to encode and decode [Ethereum RLP](https://github.com/ethereum/wiki/wiki/RLP). Adapted from the [EthereumJS implementation](https://github.com/ethereumjs/rlp/blob/0ce09db81fc303fcee593f7cc094ba44015f9b92/index.js)
 */
-module.exports = {
+export {
   decode,
   encode
 };
diff --git a/packages/util-rlp/test/getTests.js b/packages/util-rlp/test/getTests.js
index bfa1f0506..7b46f323c 100644
--- a/packages/util-rlp/test/getTests.js
+++ b/packages/util-rlp/test/getTests.js
@@ -2,12 +2,12 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const BN = require('bn.js');
-const { getSingleFile } = require('ethereumjs-testing');
+import BN from 'bn.js';
+import { getSingleFile } from 'ethereumjs-testing';
 
-const bnToU8a = require('@polkadot/util/bn/toU8a');
+import bnToU8a from '@polkadot/util/bn/toU8a';
 
-module.exports = function getTests (file) {
+export default function getTests (file) {
   const tests = getSingleFile(file);
 
   return Object.keys(tests).map((name) => ({
@@ -17,4 +17,4 @@ module.exports = function getTests (file) {
       : bnToU8a(new BN(tests[name].in.slice(1))),
     output: `0x${tests[name].out.toLowerCase()}`
   }));
-};
+}
diff --git a/packages/util-triedb/package.json b/packages/util-triedb/package.json
index 30db3166a..85eda7299 100644
--- a/packages/util-triedb/package.json
+++ b/packages/util-triedb/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/util-triedb",
-  "version": "0.22.11",
+  "version": "0.23.0",
   "description": "Creation of triehash values",
   "main": "index.js",
   "keywords": [
@@ -34,10 +34,10 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.0.0-beta.47",
-    "@polkadot/util": "^0.22.11",
-    "@polkadot/util-crypto": "^0.22.11",
-    "@polkadot/util-rlp": "^0.22.11",
-    "@polkadot/util-triehash": "^0.22.11",
+    "@polkadot/util": "^0.23.0",
+    "@polkadot/util-crypto": "^0.23.0",
+    "@polkadot/util-rlp": "^0.23.0",
+    "@polkadot/util-triehash": "^0.23.0",
     "leveldown": "^4.0.1",
     "levelup": "^3.0.1",
     "memdown": "^3.0.0"
diff --git a/packages/util-triedb/src/clear.js b/packages/util-triedb/src/clear.js
index 7189a2da0..0ee80b855 100644
--- a/packages/util-triedb/src/clear.js
+++ b/packages/util-triedb/src/clear.js
@@ -5,5 +5,5 @@
 
 import type { TrieDbState } from './types';
 
-module.exports = function clear (self: TrieDbState): void {
-};
+export default function clear (self: TrieDbState): void {
+}
diff --git a/packages/util-triedb/src/commit.js b/packages/util-triedb/src/commit.js
index 7aedc341a..d00ea9f64 100644
--- a/packages/util-triedb/src/commit.js
+++ b/packages/util-triedb/src/commit.js
@@ -5,5 +5,5 @@
 
 import type { TrieDbState } from './types';
 
-module.exports = function commit (self: TrieDbState): void {
-};
+export default function commit (self: TrieDbState): void {
+}
diff --git a/packages/util-triedb/src/index.js b/packages/util-triedb/src/index.js
index c03367b97..8414f5c8c 100644
--- a/packages/util-triedb/src/index.js
+++ b/packages/util-triedb/src/index.js
@@ -6,11 +6,11 @@
 // import type { LevelUp$AbstractStorage } from 'levelup';
 // import type { TrieDb } from './types';
 
-// const clear = require('./clear');
-// const commit = require('./commit');
-// const state = require('./state');
+// const clear from './clear');
+// const commit from './commit');
+// const state from './state');
 
-// module.exports = function triedb (db: LevelUp$AbstractStorage): TrieDb {
+// export default function triedb (db: LevelUp$AbstractStorage): TrieDb {
 //   const self = state(db);
 
 //   return {
diff --git a/packages/util-triedb/src/state.js b/packages/util-triedb/src/state.js
index 7eb6eb28a..6322606f2 100644
--- a/packages/util-triedb/src/state.js
+++ b/packages/util-triedb/src/state.js
@@ -6,16 +6,16 @@
 import type { LevelUp$AbstractStorage } from 'levelup';
 import type { TrieDbState } from './types';
 
-const l = require('@polkadot/util/logger')('triedb');
+import logger from '@polkadot/util/logger';
 
-const createTemp = require('./temp');
+import createTemp from './temp';
 
-module.exports = function state (db: LevelUp$AbstractStorage): TrieDbState {
+export default function state (db: LevelUp$AbstractStorage): TrieDbState {
   const storage = createTemp();
 
   return {
     db,
-    l,
+    l: logger('triedb'),
     storage
   };
-};
+}
diff --git a/packages/util-triedb/src/temp/clear.spec.js b/packages/util-triedb/src/temp/clear.spec.js
index c98331fc9..e112ab673 100644
--- a/packages/util-triedb/src/temp/clear.spec.js
+++ b/packages/util-triedb/src/temp/clear.spec.js
@@ -2,9 +2,15 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const memory = require('./index')();
+import factory from './index';
 
 describe('clear', () => {
+  let memory;
+
+  beforeEach(() => {
+    memory = factory();
+  });
+
   it('clears all values', () => {
     memory.set(new Uint8Array([1]), new Uint8Array([2]));
     memory.clear();
diff --git a/packages/util-triedb/src/temp/commit.js b/packages/util-triedb/src/temp/commit.js
index 155f76acd..e6222a063 100644
--- a/packages/util-triedb/src/temp/commit.js
+++ b/packages/util-triedb/src/temp/commit.js
@@ -6,10 +6,10 @@
 import type { Trie$Pairs } from '@polkadot/util-triehash/types';
 import type { Temp$Storage } from './types';
 
-const del = require('./del');
-const set = require('./set');
+import del from './del';
+import set from './set';
 
-module.exports = function commit (storage: Temp$Storage, values: Trie$Pairs): void {
+export default function commit (storage: Temp$Storage, values: Trie$Pairs): void {
   values.forEach(({ k, v }) => {
     if (v && v.length) {
       set(storage, k, v);
@@ -17,4 +17,4 @@ module.exports = function commit (storage: Temp$Storage, values: Trie$Pairs): vo
       del(storage, k);
     }
   });
-};
+}
diff --git a/packages/util-triedb/src/temp/commit.spec.js b/packages/util-triedb/src/temp/commit.spec.js
index 09f61f9b2..957fb6715 100644
--- a/packages/util-triedb/src/temp/commit.spec.js
+++ b/packages/util-triedb/src/temp/commit.spec.js
@@ -2,15 +2,17 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const memory = require('./index')();
+import factory from './index';
 
 describe('commit', () => {
+  let memory;
   const k1 = new Uint8Array([1]);
   const k2 = new Uint8Array([2]);
   const v1 = new Uint8Array([9]);
   const v2 = new Uint8Array([8]);
 
   beforeEach(() => {
+    memory = factory();
     memory.commit([
       { k: k1, v: v1 }
     ]);
diff --git a/packages/util-triedb/src/temp/del.js b/packages/util-triedb/src/temp/del.js
index be2cf98fa..c897a0128 100644
--- a/packages/util-triedb/src/temp/del.js
+++ b/packages/util-triedb/src/temp/del.js
@@ -5,6 +5,6 @@
 
 import type { Temp$Storage } from './types';
 
-module.exports = function del (storage: Temp$Storage, k: Uint8Array): void {
+export default function del (storage: Temp$Storage, k: Uint8Array): void {
   delete storage[k];
-};
+}
diff --git a/packages/util-triedb/src/temp/del.spec.js b/packages/util-triedb/src/temp/del.spec.js
index 9a38f7de6..2e43bc37d 100644
--- a/packages/util-triedb/src/temp/del.spec.js
+++ b/packages/util-triedb/src/temp/del.spec.js
@@ -2,9 +2,15 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const memory = require('./index')();
+import factory from './index';
 
 describe('del', () => {
+  let memory;
+
+  beforeEach(() => {
+    memory = factory();
+  });
+
   it('removes a value', () => {
     memory.set(new Uint8Array([1]), new Uint8Array([2]));
     memory.del(new Uint8Array([1]));
diff --git a/packages/util-triedb/src/temp/get.js b/packages/util-triedb/src/temp/get.js
index 6b8fdd37b..8219addfb 100644
--- a/packages/util-triedb/src/temp/get.js
+++ b/packages/util-triedb/src/temp/get.js
@@ -5,10 +5,10 @@
 
 import type { Temp$Storage } from './types';
 
-module.exports = function get (storage: Temp$Storage, k: Uint8Array): Uint8Array | null {
+export default function get (storage: Temp$Storage, k: Uint8Array): Uint8Array | null {
   const value = storage[k];
 
   return value && value.v
     ? value.v.slice()
     : null;
-};
+}
diff --git a/packages/util-triedb/src/temp/index.js b/packages/util-triedb/src/temp/index.js
index 708f9fc42..14099903e 100644
--- a/packages/util-triedb/src/temp/index.js
+++ b/packages/util-triedb/src/temp/index.js
@@ -7,15 +7,15 @@ import type { Trie$Pairs } from '@polkadot/util-triehash/types';
 import type { TrieDb } from '../types';
 import type { Temp$Storage } from './types';
 
-const trieRoot = require('@polkadot/util-triehash/root');
+import trieRoot from '@polkadot/util-triehash/root';
 
-const commit = require('./commit');
-const del = require('./del');
-const get = require('./get');
-const pairs = require('./pairs');
-const set = require('./set');
+import commit from './commit';
+import del from './del';
+import get from './get';
+import pairs from './pairs';
+import set from './set';
 
-module.exports = function temp (): TrieDb {
+export default function temp (): TrieDb {
   let storage: Temp$Storage = {};
 
   return {
@@ -37,4 +37,4 @@ module.exports = function temp (): TrieDb {
     trieRoot: (): Uint8Array =>
       trieRoot(pairs(storage))
   };
-};
+}
diff --git a/packages/util-triedb/src/temp/pairs.js b/packages/util-triedb/src/temp/pairs.js
index 97f196260..b5b4bc16e 100644
--- a/packages/util-triedb/src/temp/pairs.js
+++ b/packages/util-triedb/src/temp/pairs.js
@@ -6,9 +6,9 @@
 import type { Trie$Pairs } from '@polkadot/util-triehash/types';
 import type { Temp$Storage } from './types';
 
-module.exports = function pairs (storage: Temp$Storage): Trie$Pairs {
+export default function pairs (storage: Temp$Storage): Trie$Pairs {
   // flowlint-next-line unclear-type:off
   const keys = ((Object.keys(storage): any): Array<Uint8Array>);
 
   return keys.map((k) => storage[k]);
-};
+}
diff --git a/packages/util-triedb/src/temp/set.js b/packages/util-triedb/src/temp/set.js
index cdee90336..bff452ae3 100644
--- a/packages/util-triedb/src/temp/set.js
+++ b/packages/util-triedb/src/temp/set.js
@@ -6,9 +6,9 @@
 import type { Trie$Pair } from '@polkadot/util-triehash/types';
 import type { Temp$Storage } from './types';
 
-module.exports = function set (storage: Temp$Storage, k: Uint8Array, v: Uint8Array): void {
+export default function set (storage: Temp$Storage, k: Uint8Array, v: Uint8Array): void {
   storage[k] = ({
     k: k.slice(),
     v: v.slice()
   }: Trie$Pair);
-};
+}
diff --git a/packages/util-triedb/src/temp/trieRoot.spec.js b/packages/util-triedb/src/temp/trieRoot.spec.js
index d6aed80c0..671328a63 100644
--- a/packages/util-triedb/src/temp/trieRoot.spec.js
+++ b/packages/util-triedb/src/temp/trieRoot.spec.js
@@ -2,12 +2,18 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aFromString = require('@polkadot/util/u8a/fromString');
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import u8aFromString from '@polkadot/util/u8a/fromString';
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const temp = require('./index')();
+import factory from './index';
 
 describe('trieRoot', () => {
+  let temp;
+
+  beforeEach(() => {
+    temp = factory();
+  });
+
   it('calculates the correct trieRoot', () => {
     temp.set(u8aFromString('doe'), u8aFromString('reindeer'));
     temp.set(u8aFromString('dog'), u8aFromString('puppy'));
diff --git a/packages/util-triehash/package.json b/packages/util-triehash/package.json
index 64c56fe34..0eb5eb9f5 100644
--- a/packages/util-triehash/package.json
+++ b/packages/util-triehash/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/util-triehash",
-  "version": "0.22.11",
+  "version": "0.23.0",
   "description": "Creation of triehash values",
   "main": "index.js",
   "keywords": [
@@ -34,8 +34,8 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.0.0-beta.47",
-    "@polkadot/util": "^0.22.11",
-    "@polkadot/util-crypto": "^0.22.11",
-    "@polkadot/util-rlp": "^0.22.11"
+    "@polkadot/util": "^0.23.0",
+    "@polkadot/util-crypto": "^0.23.0",
+    "@polkadot/util-rlp": "^0.23.0"
   }
 }
diff --git a/packages/util-triehash/src/encode/aux.js b/packages/util-triehash/src/encode/aux.js
index 1d56c7235..b46093737 100644
--- a/packages/util-triehash/src/encode/aux.js
+++ b/packages/util-triehash/src/encode/aux.js
@@ -5,13 +5,13 @@
 
 import type { Trie$Pairs } from '../types';
 
-const keccakAsU8a = require('@polkadot/util-crypto/keccak/asU8a');
-const rlpEncode = require('@polkadot/util-rlp/encode');
+import keccakAsU8a from '@polkadot/util-crypto/keccak/asU8a';
+import rlpEncode from '@polkadot/util-rlp/encode';
 
-const encode = require('./index');
+import encode from './index';
 
 // flowlint-next-line unclear-type:off
-module.exports = function encodeAux (pairs: Trie$Pairs, preLength: number): any {
+export default function encodeAux (pairs: Trie$Pairs, preLength: number): any {
   const encoded = encode(pairs, preLength);
   const rlped = rlpEncode(encoded);
 
@@ -20,4 +20,4 @@ module.exports = function encodeAux (pairs: Trie$Pairs, preLength: number): any
   }
 
   return keccakAsU8a(rlped);
-};
+}
diff --git a/packages/util-triehash/src/encode/hexPrefix.js b/packages/util-triehash/src/encode/hexPrefix.js
index f4ac63b98..a216975d9 100644
--- a/packages/util-triehash/src/encode/hexPrefix.js
+++ b/packages/util-triehash/src/encode/hexPrefix.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-module.exports = function encodeHexPrefix (nibbles: Uint8Array | Array<number>, isLeaf: boolean): Uint8Array {
+export default function encodeHexPrefix (nibbles: Uint8Array | Array<number>, isLeaf: boolean): Uint8Array {
   const bits = ((nibbles.length & 1) + (2 * (isLeaf ? 1 : 0))) << 4;
   const result = [];
   let offset = nibbles.length % 2;
@@ -16,4 +16,4 @@ module.exports = function encodeHexPrefix (nibbles: Uint8Array | Array<number>,
   }
 
   return new Uint8Array(result);
-};
+}
diff --git a/packages/util-triehash/src/encode/hexPrefix.spec.js b/packages/util-triehash/src/encode/hexPrefix.spec.js
index 91d92e02c..426380909 100644
--- a/packages/util-triehash/src/encode/hexPrefix.spec.js
+++ b/packages/util-triehash/src/encode/hexPrefix.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const encodeHexPrefix = require('./hexPrefix');
+import encodeHexPrefix from './hexPrefix';
 
 describe('encodeHexPrefix', () => {
   it('encodes [0, 0, 1, 2, 3, 4, 5], false', () => {
diff --git a/packages/util-triehash/src/encode/index.js b/packages/util-triehash/src/encode/index.js
index d66edb1bf..9ea85fb03 100644
--- a/packages/util-triehash/src/encode/index.js
+++ b/packages/util-triehash/src/encode/index.js
@@ -5,16 +5,13 @@
 
 import type { Trie$Pairs } from '../types';
 
-// FIXME: This is horrible, but since aux calls back into encode (and ius used by the signgular encodes below, we set the export to valid before it is used)
-module.exports = encode;
-
-const encodePairs = require('./pairs');
-const encodeShared = require('./shared');
-const encodeSingle = require('./single');
-const sharedPrefixLength = require('../util/sharedPrefixLength');
+import encodePairs from './pairs';
+import encodeShared from './shared';
+import encodeSingle from './single';
+import sharedPrefixLength from '../util/sharedPrefixLength';
 
 // flowlint-next-line unclear-type:off
-function encode (pairs: Trie$Pairs, preLength: number): Array<any> {
+export default function encode (pairs: Trie$Pairs, preLength: number): Array<any> {
   if (pairs.length === 0) {
     return [];
   }
diff --git a/packages/util-triehash/src/encode/pairs.js b/packages/util-triehash/src/encode/pairs.js
index 3ebbb9dd5..6674d4454 100644
--- a/packages/util-triehash/src/encode/pairs.js
+++ b/packages/util-triehash/src/encode/pairs.js
@@ -5,7 +5,7 @@
 
 import type { Trie$Pairs } from '../types';
 
-const encodeAux = require('./aux');
+import encodeAux from './aux';
 
 function calcLength (pairs: Trie$Pairs, preLength: number, index: number, start: number): number {
   let length = 0;
@@ -22,7 +22,7 @@ function calcLength (pairs: Trie$Pairs, preLength: number, index: number, start:
 }
 
 // flowlint-next-line unclear-type:off
-module.exports = function encodePairs (pairs: Trie$Pairs, preLength: number): Array<any> {
+export default function encodePairs (pairs: Trie$Pairs, preLength: number): Array<any> {
   const result = [];
 
   let start = preLength === pairs[0].k.length
@@ -45,4 +45,4 @@ module.exports = function encodePairs (pairs: Trie$Pairs, preLength: number): Ar
   }
 
   return result;
-};
+}
diff --git a/packages/util-triehash/src/encode/shared.js b/packages/util-triehash/src/encode/shared.js
index 69a2a2bbe..f32510a2e 100644
--- a/packages/util-triehash/src/encode/shared.js
+++ b/packages/util-triehash/src/encode/shared.js
@@ -5,11 +5,11 @@
 
 import type { Trie$Pairs } from '../types';
 
-const encodeAux = require('./aux');
-const encodeHexPrefix = require('./hexPrefix');
+import encodeAux from './aux';
+import encodeHexPrefix from './hexPrefix';
 
 // flowlint-next-line unclear-type:off
-module.exports = function encodeShared (pairs: Trie$Pairs, preLength: number, sharedLength: number): Array<any> {
+export default function encodeShared (pairs: Trie$Pairs, preLength: number, sharedLength: number): Array<any> {
   return [
     encodeHexPrefix(
       pairs[0].k.slice(preLength, sharedLength),
@@ -17,4 +17,4 @@ module.exports = function encodeShared (pairs: Trie$Pairs, preLength: number, sh
     ),
     encodeAux(pairs, sharedLength)
   ];
-};
+}
diff --git a/packages/util-triehash/src/encode/single.js b/packages/util-triehash/src/encode/single.js
index 0dc607699..181211948 100644
--- a/packages/util-triehash/src/encode/single.js
+++ b/packages/util-triehash/src/encode/single.js
@@ -5,10 +5,10 @@
 
 import type { Trie$Pair } from '../types';
 
-const encodeHexPrefix = require('./hexPrefix');
+import encodeHexPrefix from './hexPrefix';
 
 // flowlint-next-line unclear-type:off
-module.exports = function encodeSingle (pair: Trie$Pair, preLength: number): Array<any> {
+export default function encodeSingle (pair: Trie$Pair, preLength: number): Array<any> {
   return [
     encodeHexPrefix(
       pair.k.slice(preLength),
@@ -16,4 +16,4 @@ module.exports = function encodeSingle (pair: Trie$Pair, preLength: number): Arr
     ),
     pair.v
   ];
-};
+}
diff --git a/packages/util-triehash/src/index.js b/packages/util-triehash/src/index.js
index 685842a94..e395698c2 100644
--- a/packages/util-triehash/src/index.js
+++ b/packages/util-triehash/src/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const trieRoot = require('./root');
-const trieRootOrdered = require('./rootOrdered');
+import trieRoot from './root';
+import trieRootOrdered from './rootOrdered';
 
 /**
   @summary Utility methods to create [Ethereum Trie hashes](https://github.com/ethereum/wiki/wiki/Patricia-Tree)
 */
-module.exports = {
+export {
   trieRoot,
   trieRootOrdered
 };
diff --git a/packages/util-triehash/src/root.js b/packages/util-triehash/src/root.js
index 6eadffdab..83d1e9665 100644
--- a/packages/util-triehash/src/root.js
+++ b/packages/util-triehash/src/root.js
@@ -5,9 +5,9 @@
 
 import type { Trie$Pairs } from './types';
 
-const asNibbles = require('./util/asNibbles');
-const genRoot = require('./util/genRoot');
-const pairsUniq = require('./util/pairsUniq');
+import asNibbles from './util/asNibbles';
+import genRoot from './util/genRoot';
+import pairsUniq from './util/pairsUniq';
 
 /**
   @name trieRoot
@@ -24,11 +24,11 @@ const pairsUniq = require('./util/pairsUniq');
       v: u8aFromString('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa')
     }]) // => 0xd23786fb4a010da3ce639d66d5e904a11dbc02746d1ce25029e53290cabf28ab
 */
-module.exports = function trieRoot (pairs: Trie$Pairs): Uint8Array {
+export default function trieRoot (pairs: Trie$Pairs): Uint8Array {
   return genRoot(
     pairsUniq(pairs).map(({ k, v }) => ({
       k: asNibbles(k),
       v
     }))
   );
-};
+}
diff --git a/packages/util-triehash/src/root.spec.js b/packages/util-triehash/src/root.spec.js
index 9b4b58ee0..ad3a8cf78 100644
--- a/packages/util-triehash/src/root.spec.js
+++ b/packages/util-triehash/src/root.spec.js
@@ -2,10 +2,10 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aFromString = require('@polkadot/util/u8a/fromString');
-const hexToU8a = require('@polkadot/util/hex/toU8a');
+import u8aFromString from '@polkadot/util/u8a/fromString';
+import hexToU8a from '@polkadot/util/hex/toU8a';
 
-const { trieRoot } = require('./index');
+import { trieRoot } from './index';
 
 describe('trieRoot', () => {
   it('encodes empty k/v pairs', () => {
diff --git a/packages/util-triehash/src/rootOrdered.js b/packages/util-triehash/src/rootOrdered.js
index 658fd7520..c93f86616 100644
--- a/packages/util-triehash/src/rootOrdered.js
+++ b/packages/util-triehash/src/rootOrdered.js
@@ -2,11 +2,11 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const rlpEncode = require('@polkadot/util-rlp/encode');
+import rlpEncode from '@polkadot/util-rlp/encode';
 
-const asNibbles = require('./util/asNibbles');
-const genRoot = require('./util/genRoot');
-const pairsUniq = require('./util/pairsUniq');
+import asNibbles from './util/asNibbles';
+import genRoot from './util/genRoot';
+import pairsUniq from './util/pairsUniq';
 
 /**
   @name trieRootOrdered
@@ -23,7 +23,7 @@ const pairsUniq = require('./util/pairsUniq');
       u8aFromString('reindeer')
     ]) // => 0xe766d5d51b89dc39d981b41bda63248d7abce4f0225eefd023792a540bcffee3
 */
-module.exports = function trieRootOrdered (values: Array<Uint8Array>): Uint8Array {
+export default function trieRootOrdered (values: Array<Uint8Array>): Uint8Array {
   return genRoot(
     pairsUniq(
       values.map((v, index) => ({
@@ -34,4 +34,4 @@ module.exports = function trieRootOrdered (values: Array<Uint8Array>): Uint8Arra
       }))
     )
   );
-};
+}
diff --git a/packages/util-triehash/src/rootOrdered.spec.js b/packages/util-triehash/src/rootOrdered.spec.js
index 018b27342..1ffbb3443 100644
--- a/packages/util-triehash/src/rootOrdered.spec.js
+++ b/packages/util-triehash/src/rootOrdered.spec.js
@@ -2,10 +2,10 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const hexToU8a = require('@polkadot/util/hex/toU8a');
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import hexToU8a from '@polkadot/util/hex/toU8a';
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const { trieRootOrdered } = require('./index');
+import { trieRootOrdered } from './index';
 
 describe('trieRootOrdered', () => {
   // https://github.com/paritytech/parity/blob/e95b09348386d01b71901365785c5fa3aa2f7a6d/util/triehash/src/lib.rs#L42
diff --git a/packages/util-triehash/src/util/asNibbles.js b/packages/util-triehash/src/util/asNibbles.js
index f217e2ff3..bfa065f5b 100644
--- a/packages/util-triehash/src/util/asNibbles.js
+++ b/packages/util-triehash/src/util/asNibbles.js
@@ -14,7 +14,7 @@
 
     asNibbles(new Uint8Array([0x41, 0x20]) // => Uint8Array([4, 1, 2, 0])
 */
-module.exports = function asNibbles (bytes: Uint8Array | Array<number>): Uint8Array {
+export default function asNibbles (bytes: Uint8Array | Array<number>): Uint8Array {
   return bytes.reduce((result, byte, index) => {
     result.set(
       [byte >> 4, byte & 0b1111],
@@ -23,4 +23,4 @@ module.exports = function asNibbles (bytes: Uint8Array | Array<number>): Uint8Ar
 
     return result;
   }, new Uint8Array(bytes.length * 2));
-};
+}
diff --git a/packages/util-triehash/src/util/asNibbles.spec.js b/packages/util-triehash/src/util/asNibbles.spec.js
index 128bcb8c6..9785fb145 100644
--- a/packages/util-triehash/src/util/asNibbles.spec.js
+++ b/packages/util-triehash/src/util/asNibbles.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const u8aFromString = require('@polkadot/util/u8a/fromString');
+import u8aFromString from '@polkadot/util/u8a/fromString';
 
-const asNibbles = require('./asNibbles');
+import asNibbles from './asNibbles';
 
 describe('asNibbles', () => {
   it('converts an array', () => {
diff --git a/packages/util-triehash/src/util/genRoot.js b/packages/util-triehash/src/util/genRoot.js
index 9ee09df61..7c0462d30 100644
--- a/packages/util-triehash/src/util/genRoot.js
+++ b/packages/util-triehash/src/util/genRoot.js
@@ -5,12 +5,12 @@
 
 import type { Trie$Pairs } from '../types';
 
-const keccakAsU8a = require('@polkadot/util-crypto/keccak/asU8a');
-const rlpEncode = require('@polkadot/util-rlp/encode');
+import keccakAsU8a from '@polkadot/util-crypto/keccak/asU8a';
+import rlpEncode from '@polkadot/util-rlp/encode';
 
-const encode = require('../encode');
+import encode from '../encode';
 
-module.exports = function genRoot (pairs: Trie$Pairs): Uint8Array {
+export default function genRoot (pairs: Trie$Pairs): Uint8Array {
   const encoded = encode(pairs, 0);
 
   return keccakAsU8a(
@@ -20,4 +20,4 @@ module.exports = function genRoot (pairs: Trie$Pairs): Uint8Array {
         : new Uint8Array([])
     )
   );
-};
+}
diff --git a/packages/util-triehash/src/util/pairsUniq.js b/packages/util-triehash/src/util/pairsUniq.js
index 2a864755b..01cc2c14b 100644
--- a/packages/util-triehash/src/util/pairsUniq.js
+++ b/packages/util-triehash/src/util/pairsUniq.js
@@ -5,13 +5,13 @@
 
 import type { Trie$Pair, Trie$Pairs } from '../types';
 
+import u8aToHex from '@polkadot/util/u8a/toHex';
+
 type PairMap = {
   [string]: Trie$Pair
 };
 
-const u8aToHex = require('@polkadot/util/u8a/toHex');
-
-module.exports = function pairsUniq (pairs: Trie$Pairs): Trie$Pairs {
+export default function pairsUniq (pairs: Trie$Pairs): Trie$Pairs {
   const map: PairMap = pairs.reduce((result, pair) => {
     result[u8aToHex(pair.k)] = pair;
 
@@ -22,4 +22,4 @@ module.exports = function pairsUniq (pairs: Trie$Pairs): Trie$Pairs {
     .keys(map)
     .sort()
     .map((key) => map[key]);
-};
+}
diff --git a/packages/util-triehash/src/util/pairsUniq.spec.js b/packages/util-triehash/src/util/pairsUniq.spec.js
index a7d33982f..26f9eedcb 100644
--- a/packages/util-triehash/src/util/pairsUniq.spec.js
+++ b/packages/util-triehash/src/util/pairsUniq.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const pairsUniq = require('./pairsUniq');
+import pairsUniq from './pairsUniq';
 
 describe('pairsUniq', () => {
   it('returns non-duplicated unchanged', () => {
diff --git a/packages/util-triehash/src/util/sharedLength.js b/packages/util-triehash/src/util/sharedLength.js
index fdde89679..aa868d073 100644
--- a/packages/util-triehash/src/util/sharedLength.js
+++ b/packages/util-triehash/src/util/sharedLength.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-module.exports = function getSharedLength (a: Uint8Array, b: Uint8Array): number {
+export default function getSharedLength (a: Uint8Array, b: Uint8Array): number {
   const count = Math.min(a.length, b.length);
 
   for (let index = 0; index < count; index++) {
@@ -13,4 +13,4 @@ module.exports = function getSharedLength (a: Uint8Array, b: Uint8Array): number
   }
 
   return count;
-};
+}
diff --git a/packages/util-triehash/src/util/sharedPrefixLength.js b/packages/util-triehash/src/util/sharedPrefixLength.js
index a9e9d5d00..8d294b4bc 100644
--- a/packages/util-triehash/src/util/sharedPrefixLength.js
+++ b/packages/util-triehash/src/util/sharedPrefixLength.js
@@ -5,9 +5,9 @@
 
 import type { Trie$Pairs } from '../types';
 
-const getSharedLength = require('./sharedLength');
+import getSharedLength from './sharedLength';
 
-module.exports = function sharedPrefixLength (pairs: Trie$Pairs): number {
+export default function sharedPrefixLength (pairs: Trie$Pairs): number {
   return pairs.reduce((length, { k }, index) => {
     if (index === 0) {
       return k.length;
@@ -18,4 +18,4 @@ module.exports = function sharedPrefixLength (pairs: Trie$Pairs): number {
       length
     );
   }, 0);
-};
+}
diff --git a/packages/util-triehash/src/util/sharedPrefixLength.spec.js b/packages/util-triehash/src/util/sharedPrefixLength.spec.js
index 54f5eb786..6549446ec 100644
--- a/packages/util-triehash/src/util/sharedPrefixLength.spec.js
+++ b/packages/util-triehash/src/util/sharedPrefixLength.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const sharedPrefixLength = require('./sharedPrefixLength');
+import sharedPrefixLength from './sharedPrefixLength';
 
 describe('sharedPrefixLength', () => {
   it('returns 0 where no matches found', () => {
diff --git a/packages/util/docs/README.md b/packages/util/docs/README.md
index 3d5171a8f..79a0bab02 100644
--- a/packages/util/docs/README.md
+++ b/packages/util/docs/README.md
@@ -1,6 +1,6 @@
 # Available interfaces
 
-Utility methods for this package are split into groups 
+Utility methods for this package are split into groups
 
 - [array](array.md) Utility methods that operates on arrays
 - [bn](bn.md) Utility methods to convert to and from `BN` objects
@@ -16,7 +16,7 @@ Utility methods for this package are split into groups
 
 ## assert
 
-Checks for a valid test, if not ExtError is thrown. 
+Checks for a valid test, if not ExtError is thrown.
 
 ```js
 assert (test: mixed, message: string | () => string, code: number = ExtError.CODES.ASSERT, data: mixed): void
@@ -26,7 +26,7 @@ assert (test: mixed, message: string | () => string, code: number = ExtError.COD
 Checks that `test` is a truthy value. If value is falsy (`null`, `undefined`, `false`, ...), it throws an ExtError with the supplied `message` and an optional `code` and `data`. When `test` passes, `true` is returned.
 
 ```js
-const assert = require('@polkadot/util/assert');
+const assert from '@polkadot/util/assert');
 
 assert(true, 'True should be true'); // true returned
 assert(false, 'False should not be true'); // ExtError thrown
@@ -35,7 +35,7 @@ assert(false, () => 'message'); // ExtError with 'message'
 
 ## Logger
 
-Creates a consistent log interface for messages 
+Creates a consistent log interface for messages
 
 ```js
 logger (type: string): Logger
@@ -45,14 +45,14 @@ logger (type: string): Logger
 Returns a `Logger` that has `.log`, `.error`, `.warn` and `.debug` (constrolled with environment `DEBUG=typeA,typeB`) methods. Logging is done with a consistent prefix (type of logger, date) followed by the actual message using the underlying console.
 
 ```js
-const l = require('@polkadot/util/logger')('test');
+const l from '@polkadot/util/logger')('test');
 
 l.log('blah'); // <date>     TEST: blah
 ```
 
 ## promisify
 
-Wraps an async callback into a `Promise` 
+Wraps an async callback into a `Promise`
 
 ```js
 function promisify (this: ?Object, fn: Function, ...params: Array<mixed>): Promise<any>
@@ -62,8 +62,8 @@ function promisify (this: ?Object, fn: Function, ...params: Array<mixed>): Promi
 Wraps the supplied async function `fn` that has a standard JS callback `(error: Error, result: any)` into a `Promise`, passing the supplied parameters. When `error` is set, the Promise is rejected, else the Promise resolves with the `result` value.
 
 ```js
-const promisify = require('@polkadot/util/promisify');
+const promisify from '@polkadot/util/promisify');
 
 await promisify(null, ((a, cb) => cb(null, a), true); // resolves with `true`
 await promisify(null, (cb) => cb(new Error('error!'))); // rejects with `error!`
-```
\ No newline at end of file
+```
diff --git a/packages/util/docs/ext.md b/packages/util/docs/ext.md
index 071da1baa..01e18e05e 100644
--- a/packages/util/docs/ext.md
+++ b/packages/util/docs/ext.md
@@ -1,12 +1,12 @@
 # ext
 
-Extensions to basic classes 
+Extensions to basic classes
 
 - [ExtError](#exterror) Extension to the basic JS Error.
 
 ## ExtError
 
-Extension to the basic JS Error. 
+Extension to the basic JS Error.
 
 ```js
 ExtError (message: string = '', code: number = UNKNOWN_ERROR, value: any)
@@ -16,7 +16,7 @@ ExtError (message: string = '', code: number = UNKNOWN_ERROR, value: any)
 The built-in JavaScript Error class is extended by adding a code to allow for Error categorization. In addition to the normal `stack`, `message`, the numeric `code` and `data` (mixed types) parameters are available on the object.
 
 ```js
-const { ExtError } = require('@polkadot/util');
+const { ExtError } from '@polkadot/util');
 
 throw new ExtError('some message', ExtError.CODES.METHOD_NOT_FOUND); // => error.code = -32601
-```
\ No newline at end of file
+```
diff --git a/packages/util/package.json b/packages/util/package.json
index 6f7f05f92..1f273d5df 100644
--- a/packages/util/package.json
+++ b/packages/util/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/util",
-  "version": "0.22.11",
+  "version": "0.23.0",
   "description": "A collection of useful utilities for @polkadot",
   "main": "index.js",
   "keywords": [
diff --git a/packages/util/src/array/filter.js b/packages/util/src/array/filter.js
index 4298ad4d8..aacbef5ee 100644
--- a/packages/util/src/array/filter.js
+++ b/packages/util/src/array/filter.js
@@ -3,8 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isNull = require('../is/null');
-const isUndefined = require('../is/undefined');
+import isNull from '../is/null';
+import isUndefined from '../is/undefined';
 
 /**
   @name arrayFilter
@@ -18,8 +18,8 @@ const isUndefined = require('../is/undefined');
     arrayFilter([0, void 0, true, null, false, '']); // [0, true, null, false, '']
     arrayFilter([0, void 0, true, null, false, ''], false); // [0, true, false, '']
 */
-module.exports = function arrayFilter (array: Array<mixed>, allowNulls: boolean = true): Array<mixed> {
+export default function arrayFilter (array: Array<mixed>, allowNulls: boolean = true): Array<mixed> {
   return array.filter((value) => {
     return !isUndefined(value) && (allowNulls || !isNull(value));
   });
-};
+}
diff --git a/packages/util/src/array/filter.spec.js b/packages/util/src/array/filter.spec.js
index afae8a51e..06407fac8 100644
--- a/packages/util/src/array/filter.spec.js
+++ b/packages/util/src/array/filter.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { arrayFilter } = require('./index');
+import { arrayFilter } from './index';
 
 describe('filterArray', () => {
   it('filters arrays, removing undefined', () => {
diff --git a/packages/util/src/array/index.js b/packages/util/src/array/index.js
index 983c103d5..9c98d091a 100644
--- a/packages/util/src/array/index.js
+++ b/packages/util/src/array/index.js
@@ -3,11 +3,11 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const arrayFilter = require('./filter');
+import arrayFilter from './filter';
 
 /**
   @summary Utility methods that operates on arrays
 */
-module.exports = {
+export {
   arrayFilter
 };
diff --git a/packages/util/src/assert.js b/packages/util/src/assert.js
index 06d0e5c84..bea658f96 100644
--- a/packages/util/src/assert.js
+++ b/packages/util/src/assert.js
@@ -3,8 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const ExtError = require('./ext/error');
-const isFunction = require('./is/function');
+import ExtError from './ext/error';
+import isFunction from './is/function';
 
 /**
   @name assert
@@ -13,13 +13,13 @@ const isFunction = require('./is/function');
   @description
     Checks that `test` is a truthy value. If value is falsy (`null`, `undefined`, `false`, ...), it throws an ExtError with the supplied `message` and an optional `code` and `data`. When `test` passes, `true` is returned.
   @example
-    const assert = require('@polkadot/util/assert');
+    const assert from '@polkadot/util/assert');
 
     assert(true, 'True should be true'); // true returned
     assert(false, 'False should not be true'); // ExtError thrown
     assert(false, () => 'message'); // ExtError with 'message'
 */
-module.exports = function assert (test: mixed, message: string | () => string, code: number = ExtError.CODES.ASSERT, data: mixed): boolean {
+export default function assert (test: mixed, message: string | () => string, code: number = ExtError.CODES.ASSERT, data: mixed): boolean {
   // flowlint-next-line sketchy-null:off
   if (test) {
     return true;
@@ -32,4 +32,4 @@ module.exports = function assert (test: mixed, message: string | () => string, c
 
   // $FlowFixMe we have a string here
   throw new ExtError(message, code, data);
-};
+}
diff --git a/packages/util/src/assert.spec.js b/packages/util/src/assert.spec.js
index 56fb2fa3f..47395676c 100644
--- a/packages/util/src/assert.spec.js
+++ b/packages/util/src/assert.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { assert } = require('./index');
+import { assert } from './index';
 
 describe('assert', () => {
   it('should not throw an error when test is true', () => {
diff --git a/packages/util/src/bn/fromHex.js b/packages/util/src/bn/fromHex.js
index 152b11d83..b6da9e803 100644
--- a/packages/util/src/bn/fromHex.js
+++ b/packages/util/src/bn/fromHex.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const bnFromHex = require('../hex/toBn');
+import bnFromHex from '../hex/toBn';
 
 /**
   @name bnFromHex
@@ -11,4 +11,4 @@ const bnFromHex = require('../hex/toBn');
   @summary Creates a BN.js bignumber object from a hex string.
   @alias hex/toBn
 */
-module.exports = bnFromHex;
+export default bnFromHex;
diff --git a/packages/util/src/bn/fromHex.spec.js b/packages/util/src/bn/fromHex.spec.js
index a5759deec..74e9cb496 100644
--- a/packages/util/src/bn/fromHex.spec.js
+++ b/packages/util/src/bn/fromHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { bnFromHex } = require('./index');
+import { bnFromHex } from './index';
 
 describe('bnFromHex', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/bn/index.js b/packages/util/src/bn/index.js
index 5be48c819..b96c82422 100644
--- a/packages/util/src/bn/index.js
+++ b/packages/util/src/bn/index.js
@@ -3,15 +3,15 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const bnFromHex = require('./fromHex');
-const bnToBn = require('./toBn');
-const bnToHex = require('./toHex');
-const bnToU8a = require('./toU8a');
+import bnFromHex from './fromHex';
+import bnToBn from './toBn';
+import bnToHex from './toHex';
+import bnToU8a from './toU8a';
 
 /**
   @summary Utility methods to convert to and from `BN` objects
 */
-module.exports = {
+export {
   bnFromHex,
   bnToBn,
   bnToHex,
diff --git a/packages/util/src/bn/toBn.js b/packages/util/src/bn/toBn.js
index 6bda5c109..e87f3d3d8 100644
--- a/packages/util/src/bn/toBn.js
+++ b/packages/util/src/bn/toBn.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
 /**
   @name bnToBn
@@ -18,7 +18,7 @@ const BN = require('bn.js');
     bnToBn(0x1234); // => BN(0x1234)
     bnToBn(new BN(0x1234)); // => BN(0x1234)
 */
-module.exports = function bnToBn (value?: BN | number): BN {
+export default function bnToBn (value?: BN | number): BN {
   // flowlint-next-line sketchy-null-number:off
   if (!value) {
     return new BN(0);
@@ -28,4 +28,4 @@ module.exports = function bnToBn (value?: BN | number): BN {
     // $FlowFixMe type is determined
     ? value
     : new BN(value);
-};
+}
diff --git a/packages/util/src/bn/toBn.spec.js b/packages/util/src/bn/toBn.spec.js
index 2b0bc03e5..e2cb90a17 100644
--- a/packages/util/src/bn/toBn.spec.js
+++ b/packages/util/src/bn/toBn.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const { bnToBn } = require('./index');
+import { bnToBn } from './index';
 
 describe('bnToBn', () => {
   it('converts null values to 0x00', () => {
diff --git a/packages/util/src/bn/toHex.js b/packages/util/src/bn/toHex.js
index 43b3729f4..ea1e10de4 100644
--- a/packages/util/src/bn/toHex.js
+++ b/packages/util/src/bn/toHex.js
@@ -3,10 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const hexFixLength = require('../hex/fixLength');
-const bnToBn = require('./toBn');
+import hexFixLength from '../hex/fixLength';
+import bnToBn from './toBn';
 
 const ZERO_STR = '0x00';
 
@@ -22,11 +22,11 @@ const ZERO_STR = '0x00';
 
     bnToHex(new BN(0x123456)); // => '0x123456'
 */
-module.exports = function bnToHex (value?: BN | number, bitLength: number = -1): string {
+export default function bnToHex (value?: BN | number, bitLength: number = -1): string {
   // flowlint-next-line sketchy-null-number:off
   if (!value) {
     return ZERO_STR;
   }
 
   return hexFixLength(bnToBn(value).toString(16), bitLength, true);
-};
+}
diff --git a/packages/util/src/bn/toHex.spec.js b/packages/util/src/bn/toHex.spec.js
index f2c64e8f5..d6e261d40 100644
--- a/packages/util/src/bn/toHex.spec.js
+++ b/packages/util/src/bn/toHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const { bnToHex } = require('./index');
+import { bnToHex } from './index';
 
 describe('bnToHex', () => {
   it('converts null values to 0x00', () => {
diff --git a/packages/util/src/bn/toU8a.js b/packages/util/src/bn/toU8a.js
index 2b4c6acd9..c4879ddc5 100644
--- a/packages/util/src/bn/toU8a.js
+++ b/packages/util/src/bn/toU8a.js
@@ -5,9 +5,9 @@
 
 import type BN from 'bn.js';
 
-const hexToU8a = require('../hex/toU8a');
-const bnToBn = require('./toBn');
-const bnToHex = require('./toHex');
+import hexToU8a from '../hex/toU8a';
+import bnToBn from './toBn';
+import bnToHex from './toHex';
 
 /**
   @name bnToU8a
@@ -20,7 +20,7 @@ const bnToHex = require('./toHex');
 
     bnToU8a(new BN(0x1234)); // => [0x12, 0x34]
 */
-module.exports = function bnToU8a (value?: BN | number, bitLength: number = -1, isLe: boolean = false): Uint8Array {
+export default function bnToU8a (value?: BN | number, bitLength: number = -1, isLe: boolean = false): Uint8Array {
   const byteLength = Math.ceil(bitLength / 8);
 
   // flowlint-next-line sketchy-null-number:off
@@ -44,4 +44,4 @@ module.exports = function bnToU8a (value?: BN | number, bitLength: number = -1,
   );
 
   return output;
-};
+}
diff --git a/packages/util/src/bn/toU8a.spec.js b/packages/util/src/bn/toU8a.spec.js
index 49f19bc9f..bdf0eca2a 100644
--- a/packages/util/src/bn/toU8a.spec.js
+++ b/packages/util/src/bn/toU8a.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const { bnToU8a } = require('./index');
+import { bnToU8a } from './index';
 
 describe('bnToU8a', () => {
   it('converts null values to 0x00', () => {
diff --git a/packages/util/src/buffer/fromU8a.js b/packages/util/src/buffer/fromU8a.js
index 02674a8ba..876e2501b 100644
--- a/packages/util/src/buffer/fromU8a.js
+++ b/packages/util/src/buffer/fromU8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const bufferFromU8a = require('../u8a/toBuffer');
+import bufferFromU8a from '../u8a/toBuffer';
 
 /**
   @name bufferFromU8a
@@ -11,4 +11,4 @@ const bufferFromU8a = require('../u8a/toBuffer');
   @summary Creates a Buffer object from a Uint8Array.
   @alias u8a/toBuffer
 */
-module.exports = bufferFromU8a;
+export default bufferFromU8a;
diff --git a/packages/util/src/buffer/fromU8a.spec.js b/packages/util/src/buffer/fromU8a.spec.js
index 3a2e15477..afcc8ca00 100644
--- a/packages/util/src/buffer/fromU8a.spec.js
+++ b/packages/util/src/buffer/fromU8a.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { bufferFromU8a } = require('./index');
+import { bufferFromU8a } from './index';
 
 describe('bufferFromU8a', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/buffer/index.js b/packages/util/src/buffer/index.js
index b8c0349d8..e73a1a172 100644
--- a/packages/util/src/buffer/index.js
+++ b/packages/util/src/buffer/index.js
@@ -3,13 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const bufferFromU8a = require('./fromU8a');
-const bufferToU8a = require('./toU8a');
+import bufferFromU8a from './fromU8a';
+import bufferToU8a from './toU8a';
 
 /**
   @summary Utility methods to convert to and from `Buffer` objects
 */
-module.exports = {
+export {
   bufferFromU8a,
   bufferToU8a
 };
diff --git a/packages/util/src/buffer/toU8a.js b/packages/util/src/buffer/toU8a.js
index 732de07f6..063b141ca 100644
--- a/packages/util/src/buffer/toU8a.js
+++ b/packages/util/src/buffer/toU8a.js
@@ -14,10 +14,10 @@
 
     bufferToU8a(Buffer.from([1, 2, 3]));
 */
-module.exports = function bufferToU8a (buffer?: Buffer): Uint8Array {
+export default function bufferToU8a (buffer?: Buffer): Uint8Array {
   if (!buffer) {
     return new Uint8Array([]);
   }
 
   return new Uint8Array(buffer);
-};
+}
diff --git a/packages/util/src/buffer/toU8a.spec.js b/packages/util/src/buffer/toU8a.spec.js
index 92a1841b5..4411da940 100644
--- a/packages/util/src/buffer/toU8a.spec.js
+++ b/packages/util/src/buffer/toU8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { bufferToU8a } = require('./index');
+import { bufferToU8a } from './index';
 
 describe('bufferToU8a', () => {
   it('returns an empty buffer when null provided', () => {
diff --git a/packages/util/src/ext/error.js b/packages/util/src/ext/error.js
index 28b2ec533..c8c1687a6 100644
--- a/packages/util/src/ext/error.js
+++ b/packages/util/src/ext/error.js
@@ -5,10 +5,19 @@
 
 import type { ExtErrorInterface } from '../types';
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
 const UNKNOWN = -99999;
 
+// flowlint-next-line unclear-type:off
+function extend (that: any, name: string, value: mixed): void {
+  Object.defineProperty(that, name, {
+    configurable: true,
+    enumerable: false,
+    value
+  });
+}
+
 /**
   @name ExtError
   @signature ExtError (message: string = '', code: number = UNKNOWN_ERROR, value: any)
@@ -16,11 +25,11 @@ const UNKNOWN = -99999;
   @description
     The built-in JavaScript Error class is extended by adding a code to allow for Error categorization. In addition to the normal `stack`, `message`, the numeric `code` and `data` (mixed types) parameters are available on the object.
   @example
-    const { ExtError } = require('@polkadot/util');
+    const { ExtError } from '@polkadot/util');
 
     throw new ExtError('some message', ExtError.CODES.METHOD_NOT_FOUND); // => error.code = -32601
 */
-module.exports = class ExtError extends Error implements ExtErrorInterface {
+export default class ExtError extends Error implements ExtErrorInterface {
   code: number;
   data: mixed;
   message: string;
@@ -30,23 +39,15 @@ module.exports = class ExtError extends Error implements ExtErrorInterface {
   constructor (message: string = '', code: number = UNKNOWN, data: mixed) {
     super();
 
-    const extend = (name: string, value: mixed): void => {
-      Object.defineProperty(this, name, {
-        configurable: true,
-        enumerable: false,
-        value
-      });
-    };
-
-    extend('message', String(message));
-    extend('name', this.constructor.name);
-    extend('data', data);
-    extend('code', code);
+    extend(this, 'message', String(message));
+    extend(this, 'name', this.constructor.name);
+    extend(this, 'data', data);
+    extend(this, 'code', code);
 
     if (isFunction(Error.captureStackTrace)) {
       Error.captureStackTrace(this, this.constructor);
     } else {
-      extend('stack', (new Error(message)).stack);
+      extend(this, 'stack', (new Error(message)).stack);
     }
   }
 
@@ -56,4 +57,4 @@ module.exports = class ExtError extends Error implements ExtErrorInterface {
     INVALID_JSONRPC: -99998,
     METHOD_NOT_FOUND: -32601 // Rust client
   };
-};
+}
diff --git a/packages/util/src/ext/error.spec.js b/packages/util/src/ext/error.spec.js
index bdfaad81e..cf2b351e5 100644
--- a/packages/util/src/ext/error.spec.js
+++ b/packages/util/src/ext/error.spec.js
@@ -2,8 +2,8 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isError = require('../is/error');
-const { ExtError } = require('./index');
+import isError from '../is/error';
+import { ExtError } from './index';
 
 describe('ExtError', () => {
   describe('constructor', () => {
diff --git a/packages/util/src/ext/index.js b/packages/util/src/ext/index.js
index b233e47e1..8745e86a6 100644
--- a/packages/util/src/ext/index.js
+++ b/packages/util/src/ext/index.js
@@ -3,11 +3,11 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const ExtError = require('./error');
+import ExtError from './error';
 
 /**
   @summary Extensions to basic classes
 */
-module.exports = {
+export {
   ExtError
 };
diff --git a/packages/util/src/hex/addPrefix.js b/packages/util/src/hex/addPrefix.js
index da5aa53af..e0f85626c 100644
--- a/packages/util/src/hex/addPrefix.js
+++ b/packages/util/src/hex/addPrefix.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hasPrefix = require('./hasPrefix');
+import hasPrefix from './hasPrefix';
 
 /**
   @name hexAddPrefix
@@ -16,7 +16,7 @@ const hasPrefix = require('./hasPrefix');
 
     console.log('With prefix', hexAddPrefix('0a0b12')) // => 0x0a0b12
 */
-module.exports = function hexAddPrefix (value: ?string): string {
+export default function hexAddPrefix (value: ?string): string {
   // flowlint-next-line sketchy-null-string:off
   if (value && hasPrefix(value)) {
     return value;
@@ -28,4 +28,4 @@ module.exports = function hexAddPrefix (value: ?string): string {
     : '';
 
   return `0x${prefix}${value || ''}`;
-};
+}
diff --git a/packages/util/src/hex/addPrefix.spec.js b/packages/util/src/hex/addPrefix.spec.js
index 2c54c2da7..d607b9800 100644
--- a/packages/util/src/hex/addPrefix.spec.js
+++ b/packages/util/src/hex/addPrefix.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexAddPrefix } = require('./index');
+import { hexAddPrefix } from './index';
 
 describe('hexAddPrefix', () => {
   it('does not add when prefix is available', () => {
diff --git a/packages/util/src/hex/fixLength.js b/packages/util/src/hex/fixLength.js
index c1a8857e6..69b64d3a9 100644
--- a/packages/util/src/hex/fixLength.js
+++ b/packages/util/src/hex/fixLength.js
@@ -3,8 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexAddPrefix = require('./addPrefix');
-const hexStripPrefix = require('./stripPrefix');
+import hexAddPrefix from './addPrefix';
+import hexStripPrefix from './stripPrefix';
 
 /**
   @name hexFixLength
@@ -19,7 +19,7 @@ const hexStripPrefix = require('./stripPrefix');
     console.log('fixed', hexFixLength('0x12', 16, true)) // => 0x0012
     console.log('fixed', hexFixLength('0x0012', 8)) // => 0x12
 */
-module.exports = function hexFixLength (value: string, bitLength: number = -1, withPadding: boolean = false): string {
+export default function hexFixLength (value: string, bitLength: number = -1, withPadding: boolean = false): string {
   const strLength = Math.ceil(bitLength / 4);
   const hexLength = strLength + 2;
 
@@ -38,4 +38,4 @@ module.exports = function hexFixLength (value: string, bitLength: number = -1, w
   return hexAddPrefix(
     `${'0'.repeat(strLength)}${hexStripPrefix(value)}`.slice(-1 * strLength)
   );
-};
+}
diff --git a/packages/util/src/hex/fixLength.spec.js b/packages/util/src/hex/fixLength.spec.js
index 1c879b44c..fd3d9b7c7 100644
--- a/packages/util/src/hex/fixLength.spec.js
+++ b/packages/util/src/hex/fixLength.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexFixLength } = require('./index');
+import { hexFixLength } from './index';
 
 describe('hexFixLength', () => {
   it('returns bitLength === -1 as-is', () => {
diff --git a/packages/util/src/hex/fromBn.js b/packages/util/src/hex/fromBn.js
index cdf94be46..9665e9ec1 100644
--- a/packages/util/src/hex/fromBn.js
+++ b/packages/util/src/hex/fromBn.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexFromBn = require('../bn/toHex');
+import hexFromBn from '../bn/toHex';
 
 /**
   @name hexFromBn
@@ -11,4 +11,4 @@ const hexFromBn = require('../bn/toHex');
   @summary Creates a hex value from a BN.js bignumber object.
   @alias bn/toHex
 */
-module.exports = hexFromBn;
+export default hexFromBn;
diff --git a/packages/util/src/hex/fromBn.spec.js b/packages/util/src/hex/fromBn.spec.js
index 3dd04438b..402ce03d3 100644
--- a/packages/util/src/hex/fromBn.spec.js
+++ b/packages/util/src/hex/fromBn.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { hexFromBn } = require('./index');
+import { hexFromBn } from './index';
 
 describe('hexFromBn', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/hex/fromNumber.js b/packages/util/src/hex/fromNumber.js
index 57ca1428d..6c27dfc1c 100644
--- a/packages/util/src/hex/fromNumber.js
+++ b/packages/util/src/hex/fromNumber.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexFromNumber = require('../number/toHex');
+import hexFromNumber from '../number/toHex';
 
 /**
   @name hexFromNumber
@@ -11,4 +11,4 @@ const hexFromNumber = require('../number/toHex');
   @summary Creates a hex value from a number.
   @alias number/toHex
 */
-module.exports = hexFromNumber;
+export default hexFromNumber;
diff --git a/packages/util/src/hex/fromNumber.spec.js b/packages/util/src/hex/fromNumber.spec.js
index b7d263891..073338409 100644
--- a/packages/util/src/hex/fromNumber.spec.js
+++ b/packages/util/src/hex/fromNumber.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { hexFromNumber } = require('./index');
+import { hexFromNumber } from './index';
 
 describe('hexFromNumber', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/hex/hasPrefix.js b/packages/util/src/hex/hasPrefix.js
index 74c3283ec..ae063f4ce 100644
--- a/packages/util/src/hex/hasPrefix.js
+++ b/packages/util/src/hex/hasPrefix.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isHex = require('../is/hex');
+import isHex from '../is/hex';
 
 /**
   @name hexHasPrefix
@@ -16,7 +16,7 @@ const isHex = require('../is/hex');
 
     console.log('has prefix', hexHasPrefix('0x1234')); // => true
 */
-module.exports = function hexHasPrefix (value: ?string): boolean {
+export default function hexHasPrefix (value: ?string): boolean {
   // flowlint-next-line sketchy-null-string:off
   return !!(value && isHex(value, -1, true) && value.substr(0, 2) === '0x');
-};
+}
diff --git a/packages/util/src/hex/hasPrefix.spec.js b/packages/util/src/hex/hasPrefix.spec.js
index ddcb541a6..8bab73399 100644
--- a/packages/util/src/hex/hasPrefix.spec.js
+++ b/packages/util/src/hex/hasPrefix.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexHasPrefix } = require('./index');
+import { hexHasPrefix } from './index';
 
 describe('hexHasPrefix', () => {
   it('returns true when hex prefix is found', () => {
diff --git a/packages/util/src/hex/index.js b/packages/util/src/hex/index.js
index 543c938a9..d6452bc87 100644
--- a/packages/util/src/hex/index.js
+++ b/packages/util/src/hex/index.js
@@ -3,20 +3,20 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexAddPrefix = require('./addPrefix');
-const hexFixLength = require('./fixLength');
-const hexFromBn = require('./fromBn');
-const hexFromNumber = require('./fromNumber');
-const hexHasPrefix = require('./hasPrefix');
-const hexStripPrefix = require('./stripPrefix');
-const hexToBn = require('./toBn');
-const hexToNumber = require('./toNumber');
-const hexToU8a = require('./toU8a');
+import hexAddPrefix from './addPrefix';
+import hexFixLength from './fixLength';
+import hexFromBn from './fromBn';
+import hexFromNumber from './fromNumber';
+import hexHasPrefix from './hasPrefix';
+import hexStripPrefix from './stripPrefix';
+import hexToBn from './toBn';
+import hexToNumber from './toNumber';
+import hexToU8a from './toU8a';
 
 /**
   @summary Internal utilities to create and test for hex values
 */
-module.exports = {
+export {
   hexAddPrefix,
   hexFixLength,
   hexFromBn,
diff --git a/packages/util/src/hex/stripPrefix.js b/packages/util/src/hex/stripPrefix.js
index 6aba30078..86a3fe63c 100644
--- a/packages/util/src/hex/stripPrefix.js
+++ b/packages/util/src/hex/stripPrefix.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hasPrefix = require('./hasPrefix');
+import hasPrefix from './hasPrefix';
 
 const UNPREFIX_HEX_REGEX = /^[a-fA-F0-9]+$/;
 
@@ -18,7 +18,7 @@ const UNPREFIX_HEX_REGEX = /^[a-fA-F0-9]+$/;
 
     console.log('stripped', hexStripPrefix('0x1234')); // => 1234
 */
-module.exports = function hexStripPrefix (value: ?string): string {
+export default function hexStripPrefix (value: ?string): string {
   // flowlint-next-line sketchy-null-string:off
   if (!value) {
     return '';
@@ -33,4 +33,4 @@ module.exports = function hexStripPrefix (value: ?string): string {
   }
 
   throw new Error(`Invalid hex ${value} passed to hexStripPrefix`);
-};
+}
diff --git a/packages/util/src/hex/stripPrefix.spec.js b/packages/util/src/hex/stripPrefix.spec.js
index ff3a86426..e1b33b3f2 100644
--- a/packages/util/src/hex/stripPrefix.spec.js
+++ b/packages/util/src/hex/stripPrefix.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexStripPrefix } = require('./index');
+import { hexStripPrefix } from './index';
 
 describe('hexStripPrefix', () => {
   it('returns an empty string when null value supplied', () => {
diff --git a/packages/util/src/hex/toBn.js b/packages/util/src/hex/toBn.js
index 346d97a69..1054db541 100644
--- a/packages/util/src/hex/toBn.js
+++ b/packages/util/src/hex/toBn.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const hexStripPrefix = require('./stripPrefix');
+import hexStripPrefix from './stripPrefix';
 
 function reverse (value: string): string {
   return (value.match(new RegExp('.{1,2}', 'g')) || [])
@@ -24,7 +24,7 @@ function reverse (value: string): string {
 
     hexToBn('0x123480001f'); // => BN(0x123480001f)
 */
-module.exports = function hexToBn (_value?: string, isLe: boolean = false): BN {
+export default function hexToBn (_value?: string, isLe: boolean = false): BN {
   // flowlint-next-line sketchy-null-string:off
   if (!_value) {
     return new BN(0);
@@ -33,4 +33,4 @@ module.exports = function hexToBn (_value?: string, isLe: boolean = false): BN {
   const value = hexStripPrefix(_value);
 
   return new BN((isLe ? reverse(value) : value) || '00', 16);
-};
+}
diff --git a/packages/util/src/hex/toBn.spec.js b/packages/util/src/hex/toBn.spec.js
index 5f3725cc3..e9ce81bee 100644
--- a/packages/util/src/hex/toBn.spec.js
+++ b/packages/util/src/hex/toBn.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexToBn } = require('./index');
+import { hexToBn } from './index';
 
 describe('hexToBn', () => {
   it('converts prefixed hex values to BN', () => {
diff --git a/packages/util/src/hex/toNumber.js b/packages/util/src/hex/toNumber.js
index 07ca09f2f..44b38cd07 100644
--- a/packages/util/src/hex/toNumber.js
+++ b/packages/util/src/hex/toNumber.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexToBn = require('./toBn');
+import hexToBn from './toBn';
 
 /**
   @name hexToNumber
@@ -16,11 +16,11 @@ const hexToBn = require('./toBn');
 
     hexToNumber('0x1234'); // => 0x1234
 */
-module.exports = function hexToNumber (value?: string): number {
+export default function hexToNumber (value?: string): number {
   // flowlint-next-line sketchy-null-string:off
   if (!value) {
     return NaN;
   }
 
   return hexToBn(value).toNumber();
-};
+}
diff --git a/packages/util/src/hex/toNumber.spec.js b/packages/util/src/hex/toNumber.spec.js
index 3bde50c29..e54018fa5 100644
--- a/packages/util/src/hex/toNumber.spec.js
+++ b/packages/util/src/hex/toNumber.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexToNumber } = require('./index');
+import { hexToNumber } from './index';
 
 describe('hexToNumber', () => {
   it('converts an empty to NaN', () => {
diff --git a/packages/util/src/hex/toU8a.js b/packages/util/src/hex/toU8a.js
index 58fe45f40..c0e837cca 100644
--- a/packages/util/src/hex/toU8a.js
+++ b/packages/util/src/hex/toU8a.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const assert = require('../assert');
-const isHex = require('../is/hex');
-const hexStripPrefix = require('./stripPrefix');
+import assert from '../assert';
+import isHex from '../is/hex';
+import hexStripPrefix from './stripPrefix';
 
 /**
   @name hexToU8a
@@ -19,7 +19,7 @@ const hexStripPrefix = require('./stripPrefix');
     hexToU8a('0x80001f'); // Uint8Array([0x80, 0x00, 0x1f])
     hexToU8a('0x80001f', 32); // Uint8Array([0x00, 0x80, 0x00, 0x1f])
 */
-module.exports = function hexToU8a (_value?: string | null, bitLength: number = -1): Uint8Array {
+export default function hexToU8a (_value?: string | null, bitLength: number = -1): Uint8Array {
   // flowlint-next-line sketchy-null-string:off
   if (!_value) {
     return new Uint8Array([]);
@@ -42,4 +42,4 @@ module.exports = function hexToU8a (_value?: string | null, bitLength: number =
   }
 
   return result;
-};
+}
diff --git a/packages/util/src/hex/toU8a.spec.js b/packages/util/src/hex/toU8a.spec.js
index 4e5ac491b..d786f8fc1 100644
--- a/packages/util/src/hex/toU8a.spec.js
+++ b/packages/util/src/hex/toU8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { hexToU8a } = require('./index');
+import { hexToU8a } from './index';
 
 describe('hexToU8a', () => {
   it('returns an empty Uint8Array when null provided', () => {
diff --git a/packages/util/src/index.js b/packages/util/src/index.js
index 513cb4e98..68c466ac9 100644
--- a/packages/util/src/index.js
+++ b/packages/util/src/index.js
@@ -3,22 +3,25 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const array = require('./array');
-const assert = require('./assert');
-const bn = require('./bn');
-const buffer = require('./buffer');
-const ext = require('./ext');
-const hex = require('./hex');
-const is = require('./is');
-const logger = require('./logger');
-const number = require('./number');
-const promisify = require('./promisify');
-const string = require('./string');
-const u8a = require('./u8a');
+import assert from './assert';
+import logger from './logger';
+import promisify from './promisify';
+
+export * from './array';
+export * from './bn';
+export * from './buffer';
+export * from './ext';
+export * from './hex';
+export * from './is';
+export * from './number';
+export * from './string';
+export * from './u8a';
 
 /**
   @summary Utility methods for this package are split into groups
 */
-module.exports = Object.assign(
-  {}, array, { assert }, bn, buffer, ext, hex, is, { logger }, number, { promisify }, string, u8a
-);
+export {
+  assert,
+  logger,
+  promisify
+};
diff --git a/packages/util/src/index.spec.js b/packages/util/src/index.spec.js
index 1b2d7f36b..d536a7ab6 100644
--- a/packages/util/src/index.spec.js
+++ b/packages/util/src/index.spec.js
@@ -2,10 +2,10 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const util = require('./index');
+import { assert } from './index';
 
 describe('index', () => {
   it('exports ok', () => {
-    expect(util).toBeDefined();
+    expect(assert).toBeDefined();
   });
 });
diff --git a/packages/util/src/is/bn.js b/packages/util/src/is/bn.js
index 4350c33ca..145b7ee44 100644
--- a/packages/util/src/is/bn.js
+++ b/packages/util/src/is/bn.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
 /**
   @name isBn
@@ -17,6 +17,6 @@ const BN = require('bn.js');
 
     console.log('isBn', isBn(new BN(1))); // => true
 */
-module.exports = function isBn (value: mixed): boolean {
+export default function isBn (value: mixed): boolean {
   return BN.isBN(value);
-};
+}
diff --git a/packages/util/src/is/bn.spec.js b/packages/util/src/is/bn.spec.js
index 094a87b1e..45151afff 100644
--- a/packages/util/src/is/bn.spec.js
+++ b/packages/util/src/is/bn.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const { isBn } = require('./index');
+import { isBn } from './index';
 
 describe('isBN', () => {
   it('returns true when a BN value', () => {
diff --git a/packages/util/src/is/boolean.js b/packages/util/src/is/boolean.js
index d01c1431b..d7bc32b4e 100644
--- a/packages/util/src/is/boolean.js
+++ b/packages/util/src/is/boolean.js
@@ -14,6 +14,6 @@
 
     isBoolean(false); // => true
 */
-module.exports = function isBoolean (value: mixed): boolean {
+export default function isBoolean (value: mixed): boolean {
   return typeof value === 'boolean';
-};
+}
diff --git a/packages/util/src/is/boolean.spec.js b/packages/util/src/is/boolean.spec.js
index 8b40dc24c..9b6af314f 100644
--- a/packages/util/src/is/boolean.spec.js
+++ b/packages/util/src/is/boolean.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isBoolean } = require('./index');
+import { isBoolean } from './index';
 
 describe('isBoolean', () => {
   it('returns true on false', () => {
diff --git a/packages/util/src/is/buffer.js b/packages/util/src/is/buffer.js
index 3db59ecfc..281a7254e 100644
--- a/packages/util/src/is/buffer.js
+++ b/packages/util/src/is/buffer.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isInstanceOf = require('./instanceOf');
+import isInstanceOf from './instanceOf';
 
 /**
   @name isBuffer
@@ -16,6 +16,6 @@ const isInstanceOf = require('./instanceOf');
 
     console.log('isBuffer', isBuffer(Buffer.from([]))); // => true
 */
-module.exports = function isBuffer (value: mixed): boolean {
+export default function isBuffer (value: mixed): boolean {
   return isInstanceOf(value, Buffer);
-};
+}
diff --git a/packages/util/src/is/buffer.spec.js b/packages/util/src/is/buffer.spec.js
index 527b6d06f..91b07c235 100644
--- a/packages/util/src/is/buffer.spec.js
+++ b/packages/util/src/is/buffer.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isBuffer } = require('./index');
+import { isBuffer } from './index';
 
 describe('isBuffer', () => {
   it('returns true when a Buffer value', () => {
diff --git a/packages/util/src/is/error.js b/packages/util/src/is/error.js
index a8bb78856..241148f22 100644
--- a/packages/util/src/is/error.js
+++ b/packages/util/src/is/error.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isInstanceOf = require('./instanceOf');
+import isInstanceOf from './instanceOf';
 
 /**
   @name isError
@@ -16,6 +16,6 @@ const isInstanceOf = require('./instanceOf');
 
     console.log('isError', isError(new Error('message'))); // => true
 */
-module.exports = function isError (value: mixed): boolean {
+export default function isError (value: mixed): boolean {
   return isInstanceOf(value, Error);
-};
+}
diff --git a/packages/util/src/is/error.spec.js b/packages/util/src/is/error.spec.js
index 65f4af318..78805c27d 100644
--- a/packages/util/src/is/error.spec.js
+++ b/packages/util/src/is/error.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isError } = require('./index');
+import { isError } from './index';
 
 describe('isError', () => {
   it('returns true when an Error value', () => {
diff --git a/packages/util/src/is/function.js b/packages/util/src/is/function.js
index 45059e14b..375099f95 100644
--- a/packages/util/src/is/function.js
+++ b/packages/util/src/is/function.js
@@ -14,6 +14,6 @@
 
     console.log('isFunction', isFunction(() => false)); // => true
 */
-module.exports = function isFunction (value: mixed): boolean {
+export default function isFunction (value: mixed): boolean {
   return typeof value === 'function';
-};
+}
diff --git a/packages/util/src/is/function.spec.js b/packages/util/src/is/function.spec.js
index 2e945db2a..3e62da1a6 100644
--- a/packages/util/src/is/function.spec.js
+++ b/packages/util/src/is/function.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isFunction } = require('./index');
+import { isFunction } from './index';
 
 describe('isFunction', () => {
   it('returns true on valid functions', () => {
diff --git a/packages/util/src/is/hex.js b/packages/util/src/is/hex.js
index 3681b6249..7f89188ee 100644
--- a/packages/util/src/is/hex.js
+++ b/packages/util/src/is/hex.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isString = require('./string');
+import isString from './string';
 
 const HEX_REGEX = /^0x[a-fA-F0-9]+$/;
 
@@ -19,9 +19,9 @@ const HEX_REGEX = /^0x[a-fA-F0-9]+$/;
     isHex('0x1234'); // => true
     isHex('0x1234', 8); // => false
 */
-module.exports = function isHex (_value: mixed, bitLength: number = -1, ignoreLength: boolean = false): boolean {
+export default function isHex (_value: mixed, bitLength: number = -1, ignoreLength: boolean = false): boolean {
   // flowlint-next-line unclear-type:off
-  const value = ((_value: any): string);
+  const value: string = (_value: any);
   const isValidHex = value === '0x' || (isString(value) && HEX_REGEX.test(value));
 
   if (isValidHex && bitLength !== -1) {
@@ -29,4 +29,4 @@ module.exports = function isHex (_value: mixed, bitLength: number = -1, ignoreLe
   }
 
   return isValidHex && (ignoreLength || (value.length % 2 === 0));
-};
+}
diff --git a/packages/util/src/is/hex.spec.js b/packages/util/src/is/hex.spec.js
index 573f009a8..b476ef860 100644
--- a/packages/util/src/is/hex.spec.js
+++ b/packages/util/src/is/hex.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isHex } = require('./index');
+import { isHex } from './index';
 
 describe('isHex', () => {
   const test = '1234abcd';
diff --git a/packages/util/src/is/index.js b/packages/util/src/is/index.js
index 6d75afa6c..c3fa5f9af 100644
--- a/packages/util/src/is/index.js
+++ b/packages/util/src/is/index.js
@@ -3,26 +3,26 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isBn = require('./bn');
-const isBuffer = require('./buffer');
-const isBoolean = require('./boolean');
-const isError = require('./error');
-const isFunction = require('./function');
-const isHex = require('./hex');
-const isInstanceOf = require('./instanceOf');
-const isIp = require('./ip');
-const isNull = require('./null');
-const isNumber = require('./number');
-const isObject = require('./object');
-const isObservable = require('./observable');
-const isString = require('./string');
-const isU8a = require('./u8a');
-const isUndefined = require('./undefined');
+import isBn from './bn';
+import isBuffer from './buffer';
+import isBoolean from './boolean';
+import isError from './error';
+import isFunction from './function';
+import isHex from './hex';
+import isInstanceOf from './instanceOf';
+import isIp from './ip';
+import isNull from './null';
+import isNumber from './number';
+import isObject from './object';
+import isObservable from './observable';
+import isString from './string';
+import isU8a from './u8a';
+import isUndefined from './undefined';
 
 /**
   @summary Type checking utilities
 */
-module.exports = {
+export {
   isBn,
   isBoolean,
   isBuffer,
diff --git a/packages/util/src/is/instanceOf.js b/packages/util/src/is/instanceOf.js
index 39c32a882..f397bb9c9 100644
--- a/packages/util/src/is/instanceOf.js
+++ b/packages/util/src/is/instanceOf.js
@@ -14,6 +14,6 @@
 
     console.log('isInstanceOf', isInstanceOf(new Array(0), Array)); // => true
 */
-module.exports = function isInstanceOf (value: mixed, clazz: Class<mixed>): boolean {
+export default function isInstanceOf (value: mixed, clazz: Class<mixed>): boolean {
   return value instanceof clazz;
-};
+}
diff --git a/packages/util/src/is/instanceOf.spec.js b/packages/util/src/is/instanceOf.spec.js
index 3a59cc210..84ea0f1ff 100644
--- a/packages/util/src/is/instanceOf.spec.js
+++ b/packages/util/src/is/instanceOf.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isInstanceOf } = require('./index');
+import { isInstanceOf } from './index';
 
 describe('isInstanceOf', () => {
   it('returns true on real instances', () => {
diff --git a/packages/util/src/is/ip.js b/packages/util/src/is/ip.js
index cf8c01447..c652d4ac2 100644
--- a/packages/util/src/is/ip.js
+++ b/packages/util/src/is/ip.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-type IpTypes = 'v4' | 'v6';
+import ipRegex from 'ip-regex';
 
-const ipRegex = require('ip-regex');
+type IpTypes = 'v4' | 'v6';
 
 /**
   @name isIp
@@ -21,7 +21,7 @@ const ipRegex = require('ip-regex');
     isIp('192.168.0.1', 'v6')); // => false
     isIp('1:2:3:4:5:6:7:8', 'v4'); // => false
 */
-module.exports = function isIp (value: string, type?: IpTypes): boolean {
+export default function isIp (value: string, type?: IpTypes): boolean {
   if (type === 'v4') {
     return ipRegex.v4({ exact: true }).test(value);
   } else if (type === 'v6') {
@@ -29,4 +29,4 @@ module.exports = function isIp (value: string, type?: IpTypes): boolean {
   }
 
   return ipRegex({ exact: true }).test(value);
-};
+}
diff --git a/packages/util/src/is/ip.spec.js b/packages/util/src/is/ip.spec.js
index 1f0a2e8a8..a83c1452f 100644
--- a/packages/util/src/is/ip.spec.js
+++ b/packages/util/src/is/ip.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isIp } = require('./index');
+import { isIp } from './index';
 
 describe('isIp', () => {
   it('returns false when non-ip found', () => {
diff --git a/packages/util/src/is/null.js b/packages/util/src/is/null.js
index 0d000ddd3..5289d49a8 100644
--- a/packages/util/src/is/null.js
+++ b/packages/util/src/is/null.js
@@ -14,6 +14,6 @@
 
     console.log('isNull', isNull(null)); // => true
 */
-module.exports = function isNull (value: mixed): boolean {
+export default function isNull (value: mixed): boolean {
   return value === null;
-};
+}
diff --git a/packages/util/src/is/null.spec.js b/packages/util/src/is/null.spec.js
index 86cd2e5bb..7baf20cf8 100644
--- a/packages/util/src/is/null.spec.js
+++ b/packages/util/src/is/null.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isNull } = require('./index');
+import { isNull } from './index';
 
 describe('isNull', () => {
   it('returns true when a null value', () => {
diff --git a/packages/util/src/is/number.js b/packages/util/src/is/number.js
index 35da157f5..8a3a97aef 100644
--- a/packages/util/src/is/number.js
+++ b/packages/util/src/is/number.js
@@ -14,6 +14,6 @@
 
     console.log('isNumber', isNumber(1234)); // => true
 */
-module.exports = function isNumber (value: mixed): boolean {
+export default function isNumber (value: mixed): boolean {
   return typeof value === 'number';
-};
+}
diff --git a/packages/util/src/is/number.spec.js b/packages/util/src/is/number.spec.js
index d19d01545..df38a589b 100644
--- a/packages/util/src/is/number.spec.js
+++ b/packages/util/src/is/number.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isNumber } = require('./index');
+import { isNumber } from './index';
 
 describe('isNumber', () => {
   it('returns true on valid numbers', () => {
diff --git a/packages/util/src/is/object.js b/packages/util/src/is/object.js
index 9b5126f46..127ee75a5 100644
--- a/packages/util/src/is/object.js
+++ b/packages/util/src/is/object.js
@@ -15,6 +15,6 @@
     isObject({}); // => true
     isObject('something'); // => false
 */
-module.exports = function isObject (value: mixed): boolean {
+export default function isObject (value: mixed): boolean {
   return typeof value === 'object';
-};
+}
diff --git a/packages/util/src/is/object.spec.js b/packages/util/src/is/object.spec.js
index 341cf97af..9424989a8 100644
--- a/packages/util/src/is/object.spec.js
+++ b/packages/util/src/is/object.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isObject } = require('./index');
+import { isObject } from './index';
 
 describe('isObject', () => {
   it('returns true on valid objects', () => {
diff --git a/packages/util/src/is/observable.js b/packages/util/src/is/observable.js
index 32000bc12..502b96c04 100644
--- a/packages/util/src/is/observable.js
+++ b/packages/util/src/is/observable.js
@@ -3,8 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isFunction = require('./function');
-const isObject = require('./object');
+import isFunction from './function';
+import isObject from './object';
 
 /**
   @name isBObservable
@@ -17,7 +17,7 @@ const isObject = require('./object');
 
     console.log('isObservable', isObservable(...));
 */
-module.exports = function isObservable (value: mixed): boolean {
+export default function isObservable (value: mixed): boolean {
   // $FlowFixMe check for possibly non-existent .next
   return isObject(value) && isFunction(value.next);
-};
+}
diff --git a/packages/util/src/is/observable.spec.js b/packages/util/src/is/observable.spec.js
index b2cf0e4de..cb7ed9ab2 100644
--- a/packages/util/src/is/observable.spec.js
+++ b/packages/util/src/is/observable.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isObservable } = require('./index');
+import { isObservable } from './index';
 
 describe('isObservable', () => {
   it('returns true on valid observables', () => {
diff --git a/packages/util/src/is/string.js b/packages/util/src/is/string.js
index 0a2afc8d4..1a0bdec50 100644
--- a/packages/util/src/is/string.js
+++ b/packages/util/src/is/string.js
@@ -14,6 +14,6 @@
 
     console.log('isString', isString('test')); // => true
 */
-module.exports = function isString (value: mixed): boolean {
+export default function isString (value: mixed): boolean {
   return typeof value === 'string';
-};
+}
diff --git a/packages/util/src/is/string.spec.js b/packages/util/src/is/string.spec.js
index f4e484dbc..fd4d3a1d5 100644
--- a/packages/util/src/is/string.spec.js
+++ b/packages/util/src/is/string.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isString } = require('./index');
+import { isString } from './index';
 
 describe('isString', () => {
   it('returns true on valid strings', () => {
diff --git a/packages/util/src/is/u8a.js b/packages/util/src/is/u8a.js
index d6ecd20d4..1a41944db 100644
--- a/packages/util/src/is/u8a.js
+++ b/packages/util/src/is/u8a.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isInstanceOf = require('./instanceOf');
+import isInstanceOf from './instanceOf';
 
 /**
   @name isU8a
@@ -16,6 +16,6 @@ const isInstanceOf = require('./instanceOf');
 
     console.log('isU8a', isU8a([])); // => false
 */
-module.exports = function isU8a (value: mixed): boolean {
+export default function isU8a (value: mixed): boolean {
   return isInstanceOf(value, Uint8Array);
-};
+}
diff --git a/packages/util/src/is/u8a.spec.js b/packages/util/src/is/u8a.spec.js
index d9be1db10..d3c33940e 100644
--- a/packages/util/src/is/u8a.spec.js
+++ b/packages/util/src/is/u8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isU8a } = require('./index');
+import { isU8a } from './index';
 
 describe('isUint8Array', () => {
   it('returns false on undefined values', () => {
diff --git a/packages/util/src/is/undefined.js b/packages/util/src/is/undefined.js
index c84209bf5..2b94587a4 100644
--- a/packages/util/src/is/undefined.js
+++ b/packages/util/src/is/undefined.js
@@ -14,6 +14,6 @@
 
     console.log('isUndefined', isUndefined(void(0))); // => true
 */
-module.exports = function isUndefined (value: mixed): boolean {
+export default function isUndefined (value: mixed): boolean {
   return typeof value === 'undefined';
-};
+}
diff --git a/packages/util/src/is/undefined.spec.js b/packages/util/src/is/undefined.spec.js
index 6104b9889..383fbbede 100644
--- a/packages/util/src/is/undefined.spec.js
+++ b/packages/util/src/is/undefined.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { isUndefined } = require('./index');
+import { isUndefined } from './index';
 
 describe('isUndefined', () => {
   it('returns true on undefined values', () => {
diff --git a/packages/util/src/logger.js b/packages/util/src/logger.js
index 64f1cf795..703023769 100644
--- a/packages/util/src/logger.js
+++ b/packages/util/src/logger.js
@@ -5,13 +5,13 @@
 
 import type { Logger, Logger$Data } from './types';
 
+import chalk from 'chalk';
+
+import isFunction from './is/function';
+
 type ConsoleType = 'error' | 'log' | 'warn';
 type LogType = ConsoleType | 'debug';
 
-const chalk = require('chalk');
-
-const isFunction = require('./is/function');
-
 const logTo: { [LogType]: ConsoleType } = {
   debug: 'log',
   error: 'error',
@@ -49,11 +49,11 @@ function apply (log: LogType, type: string, values: Logger$Data): void {
   @description
     Returns a `Logger` that has `.log`, `.error`, `.warn` and `.debug` (constrolled with environment `DEBUG=typeA,typeB`) methods. Logging is done with a consistent prefix (type of logger, date) followed by the actual message using the underlying console.
   @example
-    const l = require('@polkadot/util/logger')('test');
+    const l from '@polkadot/util/logger')('test');
 
     l.log('blah'); // <date>     TEST: blah
 */
-module.exports = function logger (_type: string): Logger {
+export default function logger (_type: string): Logger {
   const type = `               ${_type.toUpperCase()}:`.slice(-16);
   let isDebug;
 
@@ -74,4 +74,4 @@ module.exports = function logger (_type: string): Logger {
     log: (...values: Logger$Data): void => apply('log', type, values),
     warn: (...values: Logger$Data): void => apply('warn', type, values)
   };
-};
+}
diff --git a/packages/util/src/logger.spec.js b/packages/util/src/logger.spec.js
index e2260039d..89fe086e6 100644
--- a/packages/util/src/logger.spec.js
+++ b/packages/util/src/logger.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { logger } = require('./index');
+import { logger } from './index';
 
 describe('logger', () => {
   let dateMatch;
diff --git a/packages/util/src/number/fromHex.js b/packages/util/src/number/fromHex.js
index 7176b1905..7b5dd3aa2 100644
--- a/packages/util/src/number/fromHex.js
+++ b/packages/util/src/number/fromHex.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const numberFromHex = require('../hex/toNumber');
+import numberFromHex from '../hex/toNumber';
 
 /**
   @name numberFromHex
@@ -11,4 +11,4 @@ const numberFromHex = require('../hex/toNumber');
   @summary Creates a Number value from a Buffer object.
   @alias hex/toNumber
 */
-module.exports = numberFromHex;
+export default numberFromHex;
diff --git a/packages/util/src/number/fromHex.spec.js b/packages/util/src/number/fromHex.spec.js
index 3ddf069f5..8e2616bc0 100644
--- a/packages/util/src/number/fromHex.spec.js
+++ b/packages/util/src/number/fromHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { numberFromHex } = require('./index');
+import { numberFromHex } from './index';
 
 describe('numberFromHex', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/number/index.js b/packages/util/src/number/index.js
index 178e0732e..a88c0b0e1 100644
--- a/packages/util/src/number/index.js
+++ b/packages/util/src/number/index.js
@@ -3,14 +3,14 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const numberFromHex = require('./fromHex');
-const numberToHex = require('./toHex');
-const numberToU8a = require('./toU8a');
+import numberFromHex from './fromHex';
+import numberToHex from './toHex';
+import numberToU8a from './toU8a';
 
 /**
   @summary Utility methods to convert to and from `number` values
 */
-module.exports = {
+export {
   numberFromHex,
   numberToHex,
   numberToU8a
diff --git a/packages/util/src/number/toHex.js b/packages/util/src/number/toHex.js
index 7f2e5b04f..8643f13d7 100644
--- a/packages/util/src/number/toHex.js
+++ b/packages/util/src/number/toHex.js
@@ -3,9 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexFixLength = require('../hex/fixLength');
-const isNull = require('../is/null');
-const isUndefined = require('../is/undefined');
+import hexFixLength from '../hex/fixLength';
+import isNull from '../is/null';
+import isUndefined from '../is/undefined';
 
 /**
   @name numberToHex
@@ -19,7 +19,7 @@ const isUndefined = require('../is/undefined');
     numberToHex(0x1234); // => '0x1234'
     numberToHex(0x1234, 32) // => 0x00001234
 */
-module.exports = function numberToHex (value?: number, bitLength: number = -1): string {
+export default function numberToHex (value?: number, bitLength: number = -1): string {
   if (isUndefined(value) || isNull(value) || isNaN(value)) {
     return '0x';
   }
@@ -29,4 +29,4 @@ module.exports = function numberToHex (value?: number, bitLength: number = -1):
     bitLength,
     true
   );
-};
+}
diff --git a/packages/util/src/number/toHex.spec.js b/packages/util/src/number/toHex.spec.js
index f22fc3828..49164215c 100644
--- a/packages/util/src/number/toHex.spec.js
+++ b/packages/util/src/number/toHex.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { numberToHex } = require('./index');
+import { numberToHex } from './index';
 
 describe('numberToHex', () => {
   it('converts undefined to 0x', () => {
diff --git a/packages/util/src/number/toU8a.js b/packages/util/src/number/toU8a.js
index 18babf780..e2716df9b 100644
--- a/packages/util/src/number/toU8a.js
+++ b/packages/util/src/number/toU8a.js
@@ -3,8 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const hexToU8a = require('../hex/toU8a');
-const numberToHex = require('./toHex');
+import hexToU8a from '../hex/toU8a';
+import numberToHex from './toHex';
 
 /**
   @name numberToU8a
@@ -17,7 +17,7 @@ const numberToHex = require('./toHex');
 
     numberToU8a(0x1234); // => [0x12, 0x34]
 */
-module.exports = function numberToU8a (value?: number, bitLength: number = -1): Uint8Array {
+export default function numberToU8a (value?: number, bitLength: number = -1): Uint8Array {
   // flowlint-next-line sketchy-null-number:off
   if (!value || isNaN(value)) {
     return new Uint8Array([]);
@@ -26,4 +26,4 @@ module.exports = function numberToU8a (value?: number, bitLength: number = -1):
   return hexToU8a(
     numberToHex(value, bitLength)
   );
-};
+}
diff --git a/packages/util/src/number/toU8a.spec.js b/packages/util/src/number/toU8a.spec.js
index a6ed42d61..0751d9b59 100644
--- a/packages/util/src/number/toU8a.spec.js
+++ b/packages/util/src/number/toU8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { numberToU8a } = require('./index');
+import { numberToU8a } from './index';
 
 describe('numberToU8a', () => {
   it('converts 0 to empty', () => {
diff --git a/packages/util/src/promisify.js b/packages/util/src/promisify.js
index 50d21386f..34d25c9ab 100644
--- a/packages/util/src/promisify.js
+++ b/packages/util/src/promisify.js
@@ -10,13 +10,13 @@
   @description
     Wraps the supplied async function `fn` that has a standard JS callback `(error: Error, result: any)` into a `Promise`, passing the supplied parameters. When `error` is set, the Promise is rejected, else the Promise resolves with the `result` value.
   @example
-    const promisify = require('@polkadot/util/promisify');
+    const promisify from '@polkadot/util/promisify');
 
     await promisify(null, ((a, cb) => cb(null, a), true); // resolves with `true`
     await promisify(null, (cb) => cb(new Error('error!'))); // rejects with `error!`
 */
 // flowlint-next-line unclear-type:off
-module.exports = function promisify (self: ?Object, fn: Function, ...params: Array<mixed>): Promise<any> {
+export default function promisify (self: ?Object, fn: Function, ...params: Array<mixed>): Promise<any> {
   return new Promise((resolve, reject) => {
     fn.apply(self, params.concat([
       // flowlint-next-line unclear-type:off
@@ -29,4 +29,4 @@ module.exports = function promisify (self: ?Object, fn: Function, ...params: Arr
       }
     ]));
   });
-};
+}
diff --git a/packages/util/src/promisify.spec.js b/packages/util/src/promisify.spec.js
index 2181d4866..ae74da477 100644
--- a/packages/util/src/promisify.spec.js
+++ b/packages/util/src/promisify.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { promisify } = require('./index');
+import { promisify } from './index';
 
 describe('promisify', () => {
   it('handles functions with no parameters (resolve)', () => {
diff --git a/packages/util/src/string/index.js b/packages/util/src/string/index.js
index d44d55f5b..f6d08bee7 100644
--- a/packages/util/src/string/index.js
+++ b/packages/util/src/string/index.js
@@ -3,11 +3,11 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const stringShorten = require('./shorten');
+import stringShorten from './shorten';
 
 /**
   @summary Utility methods to convert to work with `string` values
 */
-module.exports = {
+export {
   stringShorten
 };
diff --git a/packages/util/src/string/shorten.js b/packages/util/src/string/shorten.js
index ba2634972..be94bc97b 100644
--- a/packages/util/src/string/shorten.js
+++ b/packages/util/src/string/shorten.js
@@ -14,7 +14,7 @@
 
     stringShorten('1234567890', 2); // => 12..90
 */
-module.exports = function stringShorten (_value: mixed, prefixLength: number = 6): string {
+export default function stringShorten (_value: mixed, prefixLength: number = 6): string {
   // $FlowFixMe coerced into string (by any means)
   const value = `${_value}`;
 
@@ -23,4 +23,4 @@ module.exports = function stringShorten (_value: mixed, prefixLength: number = 6
   }
 
   return `${value.substr(0, prefixLength)}..${value.slice(-prefixLength)}`;
-};
+}
diff --git a/packages/util/src/string/shorten.spec.js b/packages/util/src/string/shorten.spec.js
index c7e0ae0df..30e2884d8 100644
--- a/packages/util/src/string/shorten.spec.js
+++ b/packages/util/src/string/shorten.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { stringShorten } = require('./index');
+import { stringShorten } from './index';
 
 describe('stringShorten', () => {
   it('returns the value as-is when <= maxLength', () => {
diff --git a/packages/util/src/syncify.js b/packages/util/src/syncify.js
index 74183e46c..276f9879c 100644
--- a/packages/util/src/syncify.js
+++ b/packages/util/src/syncify.js
@@ -3,15 +3,15 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const deasync = require('deasync');
+import deasync from 'deasync';
 
-const isError = require('./is/error');
-const isUndefined = require('./is/undefined');
+import isError from './is/error';
+import isUndefined from './is/undefined';
 
 // FIXME: This is currently for Node environments only - for Browser environments deasync is not available, we need a different solution.
 
 // flowlint-next-line unclear-type:off
-module.exports = function syncify (promise: Promise<any>): any {
+export default function syncify (promise: Promise<any>): any {
   let result;
 
   (async () => {
@@ -27,4 +27,4 @@ module.exports = function syncify (promise: Promise<any>): any {
   }
 
   return result;
-};
+}
diff --git a/packages/util/src/syncify.spec.js b/packages/util/src/syncify.spec.js
index 1091edd41..0ece2989b 100644
--- a/packages/util/src/syncify.spec.js
+++ b/packages/util/src/syncify.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const syncify = require('./syncify');
+import syncify from './syncify';
 
 describe('syncify', () => {
   it('returns the result of the promise', () => {
diff --git a/packages/util/src/u8a/concat.js b/packages/util/src/u8a/concat.js
index 5ba6da8bf..8b463db01 100644
--- a/packages/util/src/u8a/concat.js
+++ b/packages/util/src/u8a/concat.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aToU8a = require('./toU8a');
+import u8aToU8a from './toU8a';
 
 /**
   @name u8aConcat
@@ -19,7 +19,7 @@ const u8aToU8a = require('./toU8a');
       new Uint8Array([4, 5, 6])
     ); // [1, 2, 3, 4, 5, 6]
 */
-module.exports = function u8aConcat (..._list: Array<Uint8Array | string>): Uint8Array {
+export default function u8aConcat (..._list: Array<Uint8Array | string>): Uint8Array {
   const list: Array<Uint8Array> = _list.map(u8aToU8a);
   const length = list.reduce((total, item) => total + item.length, 0);
   const result = new Uint8Array(length);
@@ -31,4 +31,4 @@ module.exports = function u8aConcat (..._list: Array<Uint8Array | string>): Uint
 
     return result;
   }, result);
-};
+}
diff --git a/packages/util/src/u8a/concat.spec.js b/packages/util/src/u8a/concat.spec.js
index 3bea1325c..38ebb0df6 100644
--- a/packages/util/src/u8a/concat.spec.js
+++ b/packages/util/src/u8a/concat.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aConcat } = require('./index');
+import { u8aConcat } from './index';
 
 describe('u8aConcat', () => {
   it('concatenates arrays', () => {
diff --git a/packages/util/src/u8a/fixLength.js b/packages/util/src/u8a/fixLength.js
index c3f0859bd..cd34e1ac0 100644
--- a/packages/util/src/u8a/fixLength.js
+++ b/packages/util/src/u8a/fixLength.js
@@ -16,7 +16,7 @@
     u8aFixLength('0x12', 16) // => 0x0012
     u8aFixLength('0x1234', 8) // => 0x12
 */
-module.exports = function u8aFixLength (value: Uint8Array, bitLength: number = -1, atStart?: boolean = false): Uint8Array {
+export default function u8aFixLength (value: Uint8Array, bitLength: number = -1, atStart?: boolean = false): Uint8Array {
   const byteLength = Math.ceil(bitLength / 8);
 
   if (bitLength === -1 || value.length === byteLength) {
@@ -36,4 +36,4 @@ module.exports = function u8aFixLength (value: Uint8Array, bitLength: number = -
   }
 
   return result;
-};
+}
diff --git a/packages/util/src/u8a/fixLength.spec.js b/packages/util/src/u8a/fixLength.spec.js
index df61b7a24..b5654da5a 100644
--- a/packages/util/src/u8a/fixLength.spec.js
+++ b/packages/util/src/u8a/fixLength.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aFixLength } = require('./index');
+import { u8aFixLength } from './index';
 
 describe('u8aFixLength', () => {
   it('returns bitLength === -1 as-is', () => {
diff --git a/packages/util/src/u8a/fromBn.js b/packages/util/src/u8a/fromBn.js
index aa2d65f8c..cffb747e3 100644
--- a/packages/util/src/u8a/fromBn.js
+++ b/packages/util/src/u8a/fromBn.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aFromBn = require('../bn/toU8a');
+import u8aFromBn from '../bn/toU8a';
 
 /**
   @name u8aFromBn
@@ -11,4 +11,4 @@ const u8aFromBn = require('../bn/toU8a');
   @summary Creates a Uint8Array value from a BN object.
   @alias bn/toU8a
 */
-module.exports = u8aFromBn;
+export default u8aFromBn;
diff --git a/packages/util/src/u8a/fromBn.spec.js b/packages/util/src/u8a/fromBn.spec.js
index 3dc866465..f722b14bb 100644
--- a/packages/util/src/u8a/fromBn.spec.js
+++ b/packages/util/src/u8a/fromBn.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { u8aFromBn } = require('./index');
+import { u8aFromBn } from './index';
 
 describe('u8aFromBn', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/u8a/fromBuffer.js b/packages/util/src/u8a/fromBuffer.js
index 35a219fbf..c4f0f1e3e 100644
--- a/packages/util/src/u8a/fromBuffer.js
+++ b/packages/util/src/u8a/fromBuffer.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aFromBuffer = require('../buffer/toU8a');
+import u8aFromBuffer from '../buffer/toU8a';
 
 /**
   @name u8aFromBuffer
@@ -11,4 +11,4 @@ const u8aFromBuffer = require('../buffer/toU8a');
   @summary Creates a Uint8Array value from a Buffer object.
   @alias buffer/toU8a
 */
-module.exports = u8aFromBuffer;
+export default u8aFromBuffer;
diff --git a/packages/util/src/u8a/fromBuffer.spec.js b/packages/util/src/u8a/fromBuffer.spec.js
index 192fcfe29..0cf41a5e5 100644
--- a/packages/util/src/u8a/fromBuffer.spec.js
+++ b/packages/util/src/u8a/fromBuffer.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { u8aFromBuffer } = require('./index');
+import { u8aFromBuffer } from './index';
 
 describe('u8aFromBuffer', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/u8a/fromHex.js b/packages/util/src/u8a/fromHex.js
index 6a90ef286..c1ffc02a6 100644
--- a/packages/util/src/u8a/fromHex.js
+++ b/packages/util/src/u8a/fromHex.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aFromHex = require('../hex/toU8a');
+import u8aFromHex from '../hex/toU8a';
 
 /**
   @name u8aFromHex
@@ -11,4 +11,4 @@ const u8aFromHex = require('../hex/toU8a');
   @summary Creates a Uint8Array value from a hex string.
   @alias hex/toU8a
 */
-module.exports = u8aFromHex;
+export default u8aFromHex;
diff --git a/packages/util/src/u8a/fromHex.spec.js b/packages/util/src/u8a/fromHex.spec.js
index e716c6b48..1103e199e 100644
--- a/packages/util/src/u8a/fromHex.spec.js
+++ b/packages/util/src/u8a/fromHex.spec.js
@@ -2,9 +2,9 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const isFunction = require('../is/function');
+import isFunction from '../is/function';
 
-const { u8aFromHex } = require('./index');
+import { u8aFromHex } from './index';
 
 describe('u8aFromHex', () => {
   it('exists as a function', () => {
diff --git a/packages/util/src/u8a/fromString.js b/packages/util/src/u8a/fromString.js
index 4c3893106..483ce1167 100644
--- a/packages/util/src/u8a/fromString.js
+++ b/packages/util/src/u8a/fromString.js
@@ -14,7 +14,7 @@
 
     u8aFromString('hello'); // [0x68, 0x65, 0x6c, 0x6c, 0x6f]
 */
-module.exports = function u8aFromString (value: string): Uint8Array {
+export default function u8aFromString (value: string): Uint8Array {
   const stringArray = [];
 
   for (let index = 0; index < value.length; index++) {
@@ -24,4 +24,4 @@ module.exports = function u8aFromString (value: string): Uint8Array {
   }
 
   return new Uint8Array(stringArray);
-};
+}
diff --git a/packages/util/src/u8a/fromString.spec.js b/packages/util/src/u8a/fromString.spec.js
index 9a9719585..5bef4ffaa 100644
--- a/packages/util/src/u8a/fromString.spec.js
+++ b/packages/util/src/u8a/fromString.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aFromString } = require('./index');
+import { u8aFromString } from './index';
 
 describe('u8aFromString', () => {
   it('encodes a string byte for byte', () => {
diff --git a/packages/util/src/u8a/fromUtf8.js b/packages/util/src/u8a/fromUtf8.js
index 9feee0ad2..980884e5b 100644
--- a/packages/util/src/u8a/fromUtf8.js
+++ b/packages/util/src/u8a/fromUtf8.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-require('./polyfill/textEncoder');
+import './polyfill/textEncoder';
 
 const encoder = new TextEncoder();
 
@@ -18,11 +18,11 @@ const encoder = new TextEncoder();
 
     u8aFromUtf8('hello'); // [0x68, 0x65, 0x6c, 0x6c, 0x6f]
 */
-module.exports = function u8aFromUtf8 (value?: string): Uint8Array {
+export default function u8aFromUtf8 (value?: string): Uint8Array {
   // flowlint-next-line sketchy-null-string:off
   if (!value) {
     return new Uint8Array([]);
   }
 
   return encoder.encode(value);
-};
+}
diff --git a/packages/util/src/u8a/fromUtf8.spec.js b/packages/util/src/u8a/fromUtf8.spec.js
index 0c9200c7d..80bc599ad 100644
--- a/packages/util/src/u8a/fromUtf8.spec.js
+++ b/packages/util/src/u8a/fromUtf8.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aFromUtf8 } = require('./index');
+import { u8aFromUtf8 } from './index';
 
 describe('u8aFromUtf8', () => {
   it('decodes to an empty string for undefined', () => {
diff --git a/packages/util/src/u8a/index.js b/packages/util/src/u8a/index.js
index d708ff0d0..88bc8003c 100644
--- a/packages/util/src/u8a/index.js
+++ b/packages/util/src/u8a/index.js
@@ -3,24 +3,24 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const u8aConcat = require('./concat');
-const u8aFixLength = require('./fixLength');
-const u8aFromBn = require('./fromBn');
-const u8aFromBuffer = require('./fromBuffer');
-const u8aFromHex = require('./fromHex');
-const u8aFromUtf8 = require('./fromUtf8');
-const u8aFromString = require('./fromString');
-const u8aToBn = require('./toBn');
-const u8aToBuffer = require('./toBuffer');
-const u8aToHex = require('./toHex');
-const u8aToString = require('./toString');
-const u8aToU8a = require('./toU8a');
-const u8aToUtf8 = require('./toUtf8');
+import u8aConcat from './concat';
+import u8aFixLength from './fixLength';
+import u8aFromBn from './fromBn';
+import u8aFromBuffer from './fromBuffer';
+import u8aFromHex from './fromHex';
+import u8aFromUtf8 from './fromUtf8';
+import u8aFromString from './fromString';
+import u8aToBn from './toBn';
+import u8aToBuffer from './toBuffer';
+import u8aToHex from './toHex';
+import u8aToString from './toString';
+import u8aToU8a from './toU8a';
+import u8aToUtf8 from './toUtf8';
 
 /**
   @summary Utility methods to convert to and from `Uint8Array` objects
 */
-module.exports = {
+export {
   u8aConcat,
   u8aFixLength,
   u8aFromBn,
diff --git a/packages/util/src/u8a/toBn.js b/packages/util/src/u8a/toBn.js
index df7af7739..8f98aa073 100644
--- a/packages/util/src/u8a/toBn.js
+++ b/packages/util/src/u8a/toBn.js
@@ -3,10 +3,10 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const BN = require('bn.js');
+import BN from 'bn.js';
 
-const hexToBn = require('../hex/toBn');
-const u8aToHex = require('./toHex');
+import hexToBn from '../hex/toBn';
+import u8aToHex from './toHex';
 
 /**
   @name u8aToBn
@@ -19,9 +19,9 @@ const u8aToHex = require('./toHex');
 
     u8aToHex(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf])); // 0x68656c0f
 */
-module.exports = function u8aToBn (value?: Uint8Array, isLe: boolean = false): BN {
+export default function u8aToBn (value?: Uint8Array, isLe: boolean = false): BN {
   return hexToBn(
     u8aToHex(value),
     isLe
   );
-};
+}
diff --git a/packages/util/src/u8a/toBn.spec.js b/packages/util/src/u8a/toBn.spec.js
index c0812f1b4..6cf050897 100644
--- a/packages/util/src/u8a/toBn.spec.js
+++ b/packages/util/src/u8a/toBn.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aToBn } = require('./index');
+import { u8aToBn } from './index';
 
 describe('u8aToBn', () => {
   it('converts values', () => {
diff --git a/packages/util/src/u8a/toBuffer.js b/packages/util/src/u8a/toBuffer.js
index 4d0f17ae9..170bd0a90 100644
--- a/packages/util/src/u8a/toBuffer.js
+++ b/packages/util/src/u8a/toBuffer.js
@@ -14,10 +14,10 @@
 
     console.log('Buffer', u8aToBuffer('0x123480001f'));
 */
-module.exports = function u8aToBuffer (value?: Uint8Array): Buffer {
+export default function u8aToBuffer (value?: Uint8Array): Buffer {
   if (!value) {
     return Buffer.from([]);
   }
 
   return Buffer.from(value);
-};
+}
diff --git a/packages/util/src/u8a/toBuffer.spec.js b/packages/util/src/u8a/toBuffer.spec.js
index 077e3b020..7df1b1187 100644
--- a/packages/util/src/u8a/toBuffer.spec.js
+++ b/packages/util/src/u8a/toBuffer.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aToBuffer } = require('./index');
+import { u8aToBuffer } from './index';
 
 describe('u8aToBuffer', () => {
   it('returns [] when the buffer is null', () => {
diff --git a/packages/util/src/u8a/toHex.js b/packages/util/src/u8a/toHex.js
index 3ff5853bd..94a422d5f 100644
--- a/packages/util/src/u8a/toHex.js
+++ b/packages/util/src/u8a/toHex.js
@@ -14,7 +14,7 @@
 
     u8aToHex(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf])); // 0x68656c0f
 */
-module.exports = function u8aToHex (value?: Uint8Array | null, bitLength: number = -1, isPrefixed: boolean = true): string {
+export default function u8aToHex (value?: Uint8Array | null, bitLength: number = -1, isPrefixed: boolean = true): string {
   const prefix = isPrefixed
     ? '0x'
     : '';
@@ -34,4 +34,4 @@ module.exports = function u8aToHex (value?: Uint8Array | null, bitLength: number
   return value.reduce((result, item) => {
     return result + `0${item.toString(16)}`.slice(-2);
   }, prefix);
-};
+}
diff --git a/packages/util/src/u8a/toHex.spec.js b/packages/util/src/u8a/toHex.spec.js
index 03f72d274..4d4e9cb02 100644
--- a/packages/util/src/u8a/toHex.spec.js
+++ b/packages/util/src/u8a/toHex.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aToHex } = require('./index');
+import { u8aToHex } from './index';
 
 describe('u8aToHex', () => {
   it('returns empty as 0x', () => {
diff --git a/packages/util/src/u8a/toString.js b/packages/util/src/u8a/toString.js
index 61d04d2f5..970b2bfc4 100644
--- a/packages/util/src/u8a/toString.js
+++ b/packages/util/src/u8a/toString.js
@@ -14,10 +14,10 @@
 
     u8aToString(new Uint8Array([21,23,45,67])); // 21,23,45,67
 */
-module.exports = function u8aToString (value?: Uint8Array): string {
+export default function u8aToString (value?: Uint8Array): string {
   if (!value || !value.length) {
     return '';
   }
 
   return value.toString();
-};
+}
diff --git a/packages/util/src/u8a/toString.spec.js b/packages/util/src/u8a/toString.spec.js
index 9a01283ee..8fae6411b 100644
--- a/packages/util/src/u8a/toString.spec.js
+++ b/packages/util/src/u8a/toString.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aToString } = require('./index');
+import { u8aToString } from './index';
 
 describe('u8aToString', () => {
   it('decodes to an empty string for undefined', () => {
diff --git a/packages/util/src/u8a/toU8a.js b/packages/util/src/u8a/toU8a.js
index 803c7f3fa..26d0b457a 100644
--- a/packages/util/src/u8a/toU8a.js
+++ b/packages/util/src/u8a/toU8a.js
@@ -3,12 +3,12 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const isBuffer = require('../is/buffer');
-const isHex = require('../is/hex');
-const isString = require('../is/string');
-const bufferToU8a = require('../buffer/toU8a');
-const hexToU8a = require('../hex/toU8a');
-const u8aFromUtf8 = require('./fromUtf8');
+import isBuffer from '../is/buffer';
+import isHex from '../is/hex';
+import isString from '../is/string';
+import bufferToU8a from '../buffer/toU8a';
+import hexToU8a from '../hex/toU8a';
+import u8aFromUtf8 from './fromUtf8';
 
 /**
   @name u8aToU8a
@@ -22,7 +22,7 @@ const u8aFromUtf8 = require('./fromUtf8');
     u8aToU8a(new Uint8Array([0x12, 0x34]); // => Uint8Array([0x12, 0x34])
     u8aToU8a(0x1234); // => Uint8Array([0x12, 0x34])
 */
-module.exports = function u8aToU8a (value?: Buffer | Uint8Array | string | null): Uint8Array {
+export default function u8aToU8a (value?: Buffer | Uint8Array | string | null): Uint8Array {
   // flowlint-next-line sketchy-null-string:off
   if (!value) {
     return new Uint8Array(0);
@@ -45,4 +45,4 @@ module.exports = function u8aToU8a (value?: Buffer | Uint8Array | string | null)
 
   // $FlowFixMe type is determined
   return value;
-};
+}
diff --git a/packages/util/src/u8a/toU8a.spec.js b/packages/util/src/u8a/toU8a.spec.js
index d353acde3..167e0c08a 100644
--- a/packages/util/src/u8a/toU8a.spec.js
+++ b/packages/util/src/u8a/toU8a.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aToU8a } = require('./index');
+import { u8aToU8a } from './index';
 
 describe('u8aToU8a', () => {
   it('returns an empty Uint8Array when null provided', () => {
diff --git a/packages/util/src/u8a/toUtf8.js b/packages/util/src/u8a/toUtf8.js
index d98b64980..723c4f22b 100644
--- a/packages/util/src/u8a/toUtf8.js
+++ b/packages/util/src/u8a/toUtf8.js
@@ -3,7 +3,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-require('./polyfill/textDecoder');
+import './polyfill/textDecoder';
 
 const decoder = new TextDecoder('utf-8');
 
@@ -18,10 +18,10 @@ const decoder = new TextDecoder('utf-8');
 
     u8aToUtf8(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0x6f])); // hello
 */
-module.exports = function u8aToUtf8 (value?: Uint8Array): string {
+export default function u8aToUtf8 (value?: Uint8Array): string {
   if (!value || !value.length) {
     return '';
   }
 
   return decoder.decode(value);
-};
+}
diff --git a/packages/util/src/u8a/toUtf8.spec.js b/packages/util/src/u8a/toUtf8.spec.js
index f0e5d4d9f..b5a2fbec4 100644
--- a/packages/util/src/u8a/toUtf8.spec.js
+++ b/packages/util/src/u8a/toUtf8.spec.js
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-const { u8aToUtf8 } = require('./index');
+import { u8aToUtf8 } from './index';
 
 describe('u8aToUtf8', () => {
   it('decodes to an empty string for undefined', () => {
diff --git a/yarn.lock b/yarn.lock
index 096b4e13f..6dc61f335 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -664,9 +664,9 @@
     lodash "^4.17.5"
     to-fast-properties "^2.0.0"
 
-"@polkadot/dev@^0.19.25":
-  version "0.19.25"
-  resolved "https://registry.yarnpkg.com/@polkadot/dev/-/dev-0.19.25.tgz#cf63238f59b9cdc015204ff760cf0a4c2892d0e5"
+"@polkadot/dev@^0.19.28":
+  version "0.19.28"
+  resolved "https://registry.yarnpkg.com/@polkadot/dev/-/dev-0.19.28.tgz#d474cec5cb66bf6d9c96b195de2f83cc4befe3af"
   dependencies:
     "@babel/cli" "^7.0.0-beta.47"
     "@babel/core" "^7.0.0-beta.47"