fflate 0.8.3: strToU8

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 fflate.strToU8 in pkg:npm/fflate@0.8.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/fflate@0.8.3
Demonstrate these symbols/APIs:
  - fflate.strToU8

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:be5805326bdb69f59a110599b62e6eb71f12e4b49dfb6ad35841303b5aa3f7a4","constraints":{"executionContext":"node"},"contract":["assert strToU8 encodes ASCII string to Uint8Array matching UTF-8 byte representation","assert strToU8 correctly encodes multibyte UTF-8 characters into byte sequences","assert strToU8 handles empty string returning an empty Uint8Array","assert strToU8 supports latin1 mode converting characters directly to single-byte values","assert strToU8 encoded bytes can be decoded back to the original string with strFromU8"],"goal":"verify fflate.strToU8 in pkg:npm/fflate@0.8.3","kind":"HOW","packages":["pkg:npm/fflate@0.8.3"],"schemaVersion":1,"symbols":["fflate.strToU8"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/fflate@0.8.3"],"schemaVersion":1,"subject":"pkg:npm/fflate@0.8.3","symbols":["fflate.strToU8"],"verifierAdapter":"node-typescript@1"}

import { strToU8, strFromU8 } from 'fflate';

/**
 * Converts a string into a Uint8Array.
 *
 * @param {string} str - The string to encode.
 * @param {boolean} [latin1] - Whether to interpret as Latin-1.
 * @returns {Uint8Array} The encoded byte array.
 */
export function encodeStringToU8(str, latin1) {
  return strToU8(str, latin1);
}

/**
 * Converts a Uint8Array back into a string.
 *
 * @param {Uint8Array} bytes - The byte array to decode.
 * @param {boolean} [latin1] - Whether to interpret as Latin-1.
 * @returns {string} The decoded string.
 */
export function decodeU8ToString(bytes, latin1) {
  return strFromU8(bytes, latin1);
}

export { strToU8, strFromU8 };
export default strToU8;

{
  "name": "sample-fflate-strtou8",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fflate-strtou8",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "fflate": "0.8.3"
      }
    },
    "node_modules/fflate": {
      "version": "0.8.3",
      "resolved": "https://registry.npmjs.org/fflate/-/fflate-0.8.3.tgz",
      "integrity": "sha512-tbZNuJrLwGUp3zshBtdy4W+ORxZuIh8a5ilyIEQDC5rY1f3U20JMry0Ll3WBzU58EZKsEuJFXhb5gwv8CsPvgA==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-fflate-strtou8",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "fflate": "0.8.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify fflate.strToU8 in pkg:npm/fflate@0.8.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/fflate@0.8.3"
  ],
  "symbols": [
    "fflate.strToU8"
  ]
}

import assert from 'node:assert/strict';
import { strToU8, strFromU8, encodeStringToU8, decodeU8ToString } from '../index.mjs';

// 1. assert strToU8 encodes ASCII string to Uint8Array matching UTF-8 byte representation
{
  const text = 'Hello CodeSampleX fflate strToU8 test!';
  const u8 = encodeStringToU8(text);
  assert.ok(u8 instanceof Uint8Array, 'strToU8 must return a Uint8Array');
  assert.strictEqual(u8.length, text.length, 'ASCII string byte length must equal string length');
  assert.deepStrictEqual(u8, new TextEncoder().encode(text), 'output bytes must match standard UTF-8 encoding');
}

// 2. assert strToU8 correctly encodes multibyte UTF-8 characters into byte sequences
{
  const text = 'Hello 🌍 세계 🎉';
  const u8 = encodeStringToU8(text);
  assert.ok(u8 instanceof Uint8Array, 'strToU8 must return a Uint8Array');
  const expected = new TextEncoder().encode(text);
  assert.strictEqual(u8.length, expected.length, 'multibyte UTF-8 byte length must match standard encoding');
  assert.deepStrictEqual(u8, expected, 'multibyte UTF-8 bytes must match TextEncoder bytes');
}

// 3. assert strToU8 handles empty string returning an empty Uint8Array
{
  const u8 = encodeStringToU8('');
  assert.ok(u8 instanceof Uint8Array, 'empty string strToU8 must return a Uint8Array');
  assert.strictEqual(u8.length, 0, 'empty string strToU8 must produce length 0 Uint8Array');
}

// 4. assert strToU8 supports latin1 mode converting characters directly to single-byte values
{
  const latin1String = 'test\x00\xFF\x80\xAB';
  const u8 = encodeStringToU8(latin1String, true);
  assert.ok(u8 instanceof Uint8Array, 'latin1 strToU8 must return a Uint8Array');
  assert.strictEqual(u8.length, latin1String.length, 'latin1 mode must map each character to exactly 1 byte');
  for (let i = 0; i < latin1String.length; i++) {
    assert.strictEqual(u8[i], latin1String.charCodeAt(i), `byte at ${i} must match character code`);
  }
}

// 5. assert strToU8 encoded bytes can be decoded back to the original string with strFromU8
{
  const original = 'Roundtrip conversion test: 12345!@#$%^&*()_+ [UTF-8: 한국어, 日本語, Deutsch, Español]';
  const encoded = encodeStringToU8(original);
  const decoded = decodeU8ToString(encoded);
  assert.strictEqual(decoded, original, 'strFromU8(strToU8(s)) must roundtrip to the original string exactly');
}

console.log('All contract assertions passed.');