Introduce @polkadot/util-rlp (#76)

* Add toU8a conversions

* Add u8a utilities

* @polkadot/rlp with encoding

* Decoding test runthrough

* Update util locations

* Convert util-triehash to use util-rlp

* Allow keccak from Uint8Array

* Pass Uint8Array to keccak input

* Update documentation

* Skip some doc generation

* Update @polkadot/dev

* Update doc typo

* Update allocations

* Retrieve tests from ethereumjs-testing

* Simplify test retrieval

* Exclude etereumjs-testing from flow

packages/util/docs/bn.md

@@ -4,6 +4,7 @@ Utility methods to convert to and from `BN` objects
 
 - [bnFromHex](#bnfromhex) Creates a BN.js bignumber object from a hex string.
 - [bnToHex](#bntohex) Creates a hex value from a BN.js bignumber object.
+- [bnToU8a](#bntou8a) Creates a Uint8Array object from a BN.
 
 ## bnFromHex
 
@@ -33,4 +34,21 @@ import BN from 'bn.js';
 import { bnToHex } from '@polkadot/util';
 
 bnToHex(new BN(0x123456)); // => '0x123456'
+```
+
+## bnToU8a
+
+Creates a Uint8Array object from a BN. 
+
+```js
+bnToU8a (value?: BN): Uint8Array
+```
+
+
+`null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `BN` input values return the actual bytes value converted to a `Uint8Array`.
+
+```js
+import { bnToU8a } from '@polkadot/util';
+
+bnToU8a(new BN(0x1234)); // => [0x12, 0x34]
 ```

packages/util/docs/number.md

@@ -6,6 +6,7 @@ Utility methods to convert to and from `number` values
 - [numberFromHex](#numberfromhex) Creates a Number value from a Buffer object.
 - [numberToBuffer](#numbertobuffer) Creates a Buffer object from a number.
 - [numberToHex](#numbertohex) Creates a hex value from a number.
+- [numberToU8a](#numbertou8a) Creates a Uint8Array object from a number.
 
 ## numberFromBuffer
 
@@ -63,4 +64,21 @@ numberToHex (value?: number): string
 import { numberToHex } from '@polkadot/util';
 
 const hex = numberToHex(0x1234); // => '0x1234'
+```
+
+## numberToU8a
+
+Creates a Uint8Array object from a number. 
+
+```js
+numberToBuffer (value?: number): Uint8Array
+```
+
+
+`null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `number` input values return the actual bytes value converted to a `Uint8Array`.
+
+```js
+import { numberToU8a } from '@polkadot/util';
+
+numberToU8a(0x1234); // => [0x12, 0x34]
 ```

packages/util/docs/u8a.md

@@ -2,6 +2,8 @@
 
 Utility methods to convert to and from `Uint8Array` objects 
 
+- [u8aConcat](#u8aconcat) Creates a concatenated Uint8Array from the inputs.
+- [u8aFromBn](#u8afrombn) Creates a Uint8Array value from a BN object.
 - [u8aFromBuffer](#u8afrombuffer) Creates a Uint8Array value from a Buffer object.
 - [u8aFromHex](#u8afromhex) Creates a Uint8Array value from a hex string.
 - [u8aFromString](#u8afromstring) Creates a Uint8Array object from a string.
@@ -10,6 +12,38 @@ Utility methods to convert to and from `Uint8Array` objects
 - [u8aToHex](#u8atohex) Creates a hex string from a Uint8Array object.
 - [u8aToUtf8](#u8atoutf8) Creates a utf-8 string from a Uint8Array object.
 
+## u8aConcat
+
+Creates a concatenated Uint8Array from the inputs. 
+
+```js
+u8aConcat (values: Array<Uint8Array>): Uint8Array
+```
+
+
+Concatenates the input arrays into a single `UInt8Array`.
+
+```js
+import { u8aConcat } from '@polkadot/util';
+
+u8aConcat([
+new Uint8Array([1, 2, 3]),
+new Uint8Array([4, 5, 6])
+]); // [1, 2, 3, 4, 5, 6]
+```
+
+## u8aFromBn
+
+Creates a Uint8Array value from a BN object. [(alias of bnToU8a)](bn.md#bntou8a)
+
+```js
+u8aFromBn (value?: BN): Uint8Array
+```
+
+
+
+
+
 ## u8aFromBuffer
 
 Creates a Uint8Array value from a Buffer object. [(alias of bufferToU8a)](buffer.md#buffertou8a)