@noble/hashes 1.4.0: utf8ToBytes

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify @noble/hashes.utf8ToBytes in pkg:npm/%40noble/hashes@1.4.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40noble/hashes@1.4.0
Demonstrate these symbols/APIs:
  - @noble/hashes.utf8ToBytes
Required runtime conditions:
  - ecosystem: golang
  - language: go
  - packageManager: go@1.26.6
  - runtime: go@1.26.6

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:ad1b9d5b80b7f9f4a32b38d861e5cf8a7d6f7b66d8981a445dca25d6c4e8a191","contract":["utf8ToBytes is exported as a function from @noble/hashes/utils","utf8ToBytes converts an empty string to an empty Uint8Array","utf8ToBytes converts ASCII strings to expected UTF-8 byte sequences","utf8ToBytes encodes multibyte Unicode strings including CJK and emojis","utf8ToBytes throws an error when input is not a string","utf8ToBytes output round-trips with TextDecoder"],"goal":"verify @noble/hashes.utf8ToBytes in pkg:npm/%40noble/hashes@1.4.0","kind":"HOW","packages":["pkg:npm/%40noble/hashes@1.4.0"],"schemaVersion":1,"symbols":["@noble/hashes.utf8ToBytes"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40noble/hashes@1.4.0"],"schemaVersion":1,"subject":"pkg:npm/%40noble/hashes@1.4.0","symbols":["@noble/hashes.utf8ToBytes"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-noble-hashes-utf8-to-bytes",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-noble-hashes-utf8-to-bytes",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@noble/hashes": "1.4.0"
      }
    },
    "node_modules/@noble/hashes": {
      "version": "1.4.0",
      "resolved": "https://registry.npmjs.org/@noble/hashes/-/hashes-1.4.0.tgz",
      "integrity": "sha512-V1JJ1WTRUqHHrOSh597hURcMqVKVGL/ea3kv0gSnEdsEZ0/+VyPghM1lMNGc00z7CIQorSvbKpuJkxvuHbvdbg==",
      "license": "MIT",
      "engines": {
        "node": ">= 16"
      },
      "funding": {
        "url": "https://paulmillr.com/funding/"
      }
    }
  }
}

{
  "name": "sample-noble-hashes-utf8-to-bytes",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room code sample for @noble/hashes utf8ToBytes",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "@noble/hashes": "1.4.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @noble/hashes.utf8ToBytes in pkg:npm/%40noble/hashes@1.4.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40noble/hashes@1.4.0"
  ],
  "symbols": [
    "@noble/hashes.utf8ToBytes"
  ],
  "runtimeConditions": {
    "ecosystem": "golang",
    "language": "go",
    "packageManager": "go@1.26.6",
    "runtime": "go@1.26.6"
  }
}

'use strict';

const { utf8ToBytes } = require('@noble/hashes/utils');

/**
 * Converts a string into a UTF-8 encoded Uint8Array.
 *
 * @param {string} str - The string to convert.
 * @returns {Uint8Array} UTF-8 byte array representation.
 */
function encodeUtf8(str) {
  return utf8ToBytes(str);
}

module.exports = {
  utf8ToBytes,
  encodeUtf8
};

import assert from 'node:assert/strict';
import { utf8ToBytes, encodeUtf8 } from '../src/index.js';
import * as utils from '@noble/hashes/utils';

// 1. utf8ToBytes is exported as a function from @noble/hashes/utils
assert.equal(typeof utils.utf8ToBytes, 'function', 'utf8ToBytes must be exported from @noble/hashes/utils');
assert.equal(typeof utf8ToBytes, 'function', 'utf8ToBytes helper must be a function');
assert.equal(typeof encodeUtf8, 'function', 'encodeUtf8 helper must be a function');

// 2. utf8ToBytes converts an empty string to an empty Uint8Array
const emptyRes = utf8ToBytes('');
assert(emptyRes instanceof Uint8Array, 'result must be a Uint8Array');
assert.equal(emptyRes.length, 0, 'empty string must produce 0-length Uint8Array');
assert.deepEqual(Array.from(emptyRes), [], 'empty string must produce empty array');

// 3. utf8ToBytes converts ASCII strings to expected UTF-8 byte sequences
const asciiStr = 'hello world';
const asciiBytes = utf8ToBytes(asciiStr);
assert(asciiBytes instanceof Uint8Array, 'result must be a Uint8Array');
assert.deepEqual(
  Array.from(asciiBytes),
  [104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100],
  'ASCII string must match expected byte values'
);
assert.deepEqual(
  Array.from(encodeUtf8(asciiStr)),
  [104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100],
  'encodeUtf8 wrapper must match utf8ToBytes output'
);

// 4. utf8ToBytes encodes multibyte Unicode strings including CJK and emojis
const unicodeStr = 'café 🚀 한글';
const unicodeBytes = utf8ToBytes(unicodeStr);
const expectedBytes = Array.from(new TextEncoder().encode(unicodeStr));
assert.deepEqual(
  Array.from(unicodeBytes),
  expectedBytes,
  'multibyte unicode string must match standard TextEncoder encoding'
);

// 5. utf8ToBytes throws an error when input is not a string
const nonStringInputs = [
  123,
  null,
  undefined,
  true,
  false,
  {},
  [],
  new Uint8Array([1, 2, 3])
];

for (const input of nonStringInputs) {
  assert.throws(
    () => utf8ToBytes(input),
    {
      name: 'Error'
    },
    `utf8ToBytes must throw for non-string input: ${String(input)}`
  );
}

// 6. utf8ToBytes output round-trips with TextDecoder
const decoder = new TextDecoder('utf-8');
const testCases = [
  '',
  'The quick brown fox jumps over the lazy dog',
  'Special symbols: !@#$%^&*()_+{}[]:;"\'<>,.?/|\\~`',
  'CJK characters: 日本語 中文 한국어',
  'Accented Latin: é, è, ê, ë, à, â, î, ï, ô, ù, û, ü, ç',
  'Emojis and surrogate pairs: 🌍🎉🔥🚀💻✨'
];

for (const tc of testCases) {
  const bytes = utf8ToBytes(tc);
  assert.equal(decoder.decode(bytes), tc, `round-trip must preserve string: "${tc}"`);
}

console.log('All @noble/hashes.utf8ToBytes contract tests passed.');