Ensure {bn, n}ToHex respects bitLength with 0 values (#1660)

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 Changes:
 
+- Ensure `{bn, n}ToHex` respects `bitLength` with 0 values
 - Upgrade dependencies to latest stable versions
 
 

packages/util/src/bi/toHex.spec.ts

@@ -10,6 +10,12 @@ describe('nToHex', (): void => {
     ).toBe('0x00');
   });
 
+  it('converts null values to 0x00000000 (with bitLength)', (): void => {
+    expect(
+      nToHex(null, { bitLength: 32 })
+    ).toBe('0x00000000');
+  });
+
   it('converts values to a prefixed hex representation', (): void => {
     expect(
       nToHex(128)

packages/util/src/bi/toHex.ts

@@ -7,15 +7,10 @@ import type { HexString, NumberOptions, ToBigInt, ToBn } from '../types';
 import { u8aToHex } from '../u8a';
 import { nToU8a } from './toU8a';
 
-/** @internal */
-const ZERO_STR = '0x00';
-
 /**
  * @name nToHex
  * @summary Creates a hex value from a bigint object.
  */
 export function nToHex <ExtToBn extends ToBn | ToBigInt> (value?: ExtToBn | BN | bigint | number | null, { bitLength, isLe = false, isNegative = false }: NumberOptions = {}): HexString {
-  return !value
-    ? ZERO_STR
-    : u8aToHex(nToU8a(value, { bitLength, isLe, isNegative }));
+  return u8aToHex(nToU8a(value || 0, { bitLength, isLe, isNegative }));
 }

packages/util/src/bi/toU8a.spec.ts

@@ -11,7 +11,7 @@ describe('nToU8a', (): void => {
   it('converts null values to 0x00', (): void => {
     expect(
       nToU8a(null)
-    ).toEqual(new Uint8Array());
+    ).toEqual(new Uint8Array(1));
   });
 
   it('converts null values to 0x00000000 (bitLength)', (): void => {

packages/util/src/bi/toU8a.ts

@@ -48,7 +48,7 @@ export function nToU8a <ExtToBn extends ToBn | ToBigInt> (value?: ExtToBn | BN |
 
   if (valueBi === _0n) {
     return bitLength === -1
-      ? new Uint8Array()
+      ? new Uint8Array(1)
       : new Uint8Array(Math.ceil((bitLength || 0) / 8));
   }
 

packages/util/src/bn/toHex.spec.ts

@@ -10,6 +10,12 @@ describe('bnToHex', (): void => {
     ).toBe('0x00');
   });
 
+  it('converts null values to 0x00000000 (with bitLength)', (): void => {
+    expect(
+      bnToHex(null, { bitLength: 32 })
+    ).toBe('0x00000000');
+  });
+
   it('converts BN values to a prefixed hex representation', (): void => {
     expect(
       bnToHex(new BN(128))

packages/util/src/bn/toHex.ts

@@ -7,8 +7,6 @@ import type { BN } from './bn';
 import { u8aToHex } from '../u8a';
 import { bnToU8a } from './toU8a';
 
-const ZERO_STR = '0x00';
-
 /**
  * @name bnToHex
  * @summary Creates a hex value from a BN.js bignumber object.
@@ -25,7 +23,5 @@ const ZERO_STR = '0x00';
  * ```
  */
 export function bnToHex <ExtToBn extends ToBn> (value?: ExtToBn | BN | bigint | number | null, { bitLength = -1, isLe = false, isNegative = false }: NumberOptions = {}): HexString {
-  return !value
-    ? ZERO_STR
-    : u8aToHex(bnToU8a(value, { bitLength, isLe, isNegative }));
+  return u8aToHex(bnToU8a(value, { bitLength, isLe, isNegative }));
 }

packages/util/src/bn/toU8a.spec.ts

@@ -11,7 +11,7 @@ describe('bnToU8a', (): void => {
   it('converts null values to 0x00', (): void => {
     expect(
       bnToU8a(null)
-    ).toEqual(new Uint8Array());
+    ).toEqual(new Uint8Array(1));
   });
 
   it('converts null values to 0x00000000 (bitLength)', (): void => {

packages/util/src/bn/toU8a.ts

@@ -30,7 +30,7 @@ export function bnToU8a <ExtToBn extends ToBn> (value?: ExtToBn | BN | bigint |
 
   if (!value) {
     return bitLength === -1
-      ? new Uint8Array()
+      ? new Uint8Array(1)
       : new Uint8Array(byteLength);
   }