Add base64 encoding and decoding functions (#145)

package.json

@@ -55,6 +55,7 @@
   "dependencies": {
     "@ethereumjs/tx": "^4.1.2",
     "@noble/hashes": "^1.3.1",
+    "@scure/base": "^1.1.3",
     "@types/debug": "^4.1.7",
     "debug": "^4.3.4",
     "semver": "^7.5.4",

src/bytes.test.ts

@@ -8,7 +8,9 @@ import {
 } from './__fixtures__';
 import {
   assertIsBytes,
+  base64ToBytes,
   bigIntToBytes,
+  bytesToBase64,
   bytesToBigInt,
   bytesToHex,
   bytesToNumber,
@@ -170,6 +172,30 @@ describe('bytesToString', () => {
   );
 });
 
+describe('bytesToBase64', () => {
+  it.each(BYTES_FIXTURES)(
+    'returns a base64 string from a byte array',
+    ({ bytes, base64 }) => {
+      expect(bytesToBase64(bytes)).toBe(base64);
+    },
+  );
+
+  it.each(LARGE_BYTES_FIXTURES)(
+    'returns a base64 string from a large byte array',
+    ({ bytes, base64 }) => {
+      expect(bytesToBase64(bytes)).toBe(base64);
+    },
+  );
+
+  it.each(INVALID_BYTES_FIXTURES)(
+    'throws an error for invalid byte arrays',
+    (value) => {
+      // @ts-expect-error Invalid type.
+      expect(() => bytesToBase64(value)).toThrow('Value must be a Uint8Array.');
+    },
+  );
+});
+
 describe('hexToBytes', () => {
   it.each(BYTES_FIXTURES)(
     'returns a byte array from a hex string',
@@ -364,6 +390,22 @@ describe('stringToBytes', () => {
   );
 });
 
+describe('base64ToBytes', () => {
+  it.each(BYTES_FIXTURES)(
+    'returns a byte array from a base64 string',
+    ({ bytes, base64 }) => {
+      expect(base64ToBytes(base64)).toStrictEqual(bytes);
+    },
+  );
+
+  it.each(LARGE_BYTES_FIXTURES)(
+    'returns a byte array from a large base64 string',
+    ({ bytes, base64 }) => {
+      expect(base64ToBytes(base64)).toStrictEqual(bytes);
+    },
+  );
+});
+
 describe('valueToBytes', () => {
   it.each(BYTES_FIXTURES)(
     'returns a byte array from a value',

src/bytes.ts

@@ -1,3 +1,5 @@
+import { base64 } from '@scure/base';
+
 import { assert } from './assert';
 import type { Hex } from './hex';
 import { add0x, assertIsHexString, remove0x } from './hex';
@@ -167,6 +169,18 @@ export function bytesToString(bytes: Uint8Array): string {
   return new TextDecoder().decode(bytes);
 }
 
+/**
+ * Convert a `Uint8Array` to a base64 encoded string.
+ *
+ * @param bytes - The bytes to convert to a base64 encoded string.
+ * @returns The base64 encoded string.
+ */
+export function bytesToBase64(bytes: Uint8Array): string {
+  assertIsBytes(bytes);
+
+  return base64.encode(bytes);
+}
+
 /**
  * Convert a hexadecimal string to a `Uint8Array`. The string can optionally be
  * prefixed with `0x`. It accepts even and odd length strings.
@@ -318,6 +332,18 @@ export function stringToBytes(value: string): Uint8Array {
   return new TextEncoder().encode(value);
 }
 
+/**
+ * Convert a base64 encoded string to a `Uint8Array`.
+ *
+ * @param value - The base64 encoded string to convert to bytes.
+ * @returns The bytes as `Uint8Array`.
+ */
+export function base64ToBytes(value: string): Uint8Array {
+  assert(typeof value === 'string', 'Value must be a string.');
+
+  return base64.decode(value);
+}
+
 /**
  * Convert a byte-like value to a `Uint8Array`. The value can be a `Uint8Array`,
  * a `bigint`, a `number`, or a `string`.

yarn.lock

@@ -1102,6 +1102,7 @@ __metadata:
     "@metamask/eslint-config-nodejs": ^12.0.0
     "@metamask/eslint-config-typescript": ^12.0.0
     "@noble/hashes": ^1.3.1
+    "@scure/base": ^1.1.3
     "@swc/cli": ^0.1.62
     "@swc/core": ^1.3.66
     "@types/debug": ^4.1.7
@@ -1273,10 +1274,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@scure/base@npm:~1.1.0":
-  version: 1.1.1
-  resolution: "@scure/base@npm:1.1.1"
-  checksum: b4fc810b492693e7e8d0107313ac74c3646970c198bbe26d7332820886fa4f09441991023ec9aa3a2a51246b74409ab5ebae2e8ef148bbc253da79ac49130309
+"@scure/base@npm:^1.1.3, @scure/base@npm:~1.1.0":
+  version: 1.1.3
+  resolution: "@scure/base@npm:1.1.3"
+  checksum: 1606ab8a4db898cb3a1ada16c15437c3bce4e25854fadc8eb03ae93cbbbac1ed90655af4b0be3da37e12056fef11c0374499f69b9e658c9e5b7b3e06353c630c
   languageName: node
   linkType: hard