fflate 0.8.3: gunzipSync

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.gunzipSync 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.gunzipSync

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:sha256:5a9953e22818c1d9b1267628d6e27a0a24f78dadef47352be07a18c9b00533b5","contract":["assert gunzipSync decompresses valid GZIP data and returns a Uint8Array","assert gunzipSync accurately restores original string content compressed with gzipSync","assert gunzipSync decompresses empty GZIP payload into an empty Uint8Array","assert gunzipSync successfully decompresses large repetitive data","assert gunzipSync throws an error when given invalid or corrupted gzip data"],"goal":"verify fflate.gunzipSync in pkg:npm/fflate@0.8.3","kind":"HOW","packages":["pkg:npm/fflate@0.8.3"],"schemaVersion":1,"symbols":["fflate.gunzipSync"]},"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.gunzipSync"],"verifierAdapter":"node-typescript@1"}

import { gunzipSync, gzipSync } from 'fflate';

/**
 * Decompresses GZIP data synchronously.
 *
 * @param {Uint8Array} data - The compressed GZIP bytes.
 * @param {object} [opts] - Decompression options.
 * @returns {Uint8Array} The decompressed bytes.
 */
export function decompressGzipSync(data, opts) {
  return gunzipSync(data, opts);
}

/**
 * Compresses data synchronously using GZIP format.
 *
 * @param {Uint8Array} data - The uncompressed input bytes.
 * @param {object} [opts] - Compression options.
 * @returns {Uint8Array} The compressed GZIP bytes.
 */
export function compressGzipSync(data, opts) {
  return gzipSync(data, opts);
}

export { gunzipSync, gzipSync };
export default gunzipSync;

{
  "name": "sample-fflate-gunzipsync",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fflate-gunzipsync",
      "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-gunzipsync",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "fflate": "0.8.3"
  }
}

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

import assert from 'node:assert/strict';
import { gunzipSync, gzipSync, decompressGzipSync, compressGzipSync } from '../index.mjs';

// 1. assert gunzipSync decompresses valid GZIP data and returns a Uint8Array
{
  const input = new TextEncoder().encode('Hello CodeSampleX gunzipSync test!');
  const compressed = compressGzipSync(input);
  const decompressed = decompressGzipSync(compressed);
  assert.ok(decompressed instanceof Uint8Array, 'gunzipSync must return a Uint8Array');
  assert.ok(decompressed.length > 0, 'decompressed output must not be empty');
}

// 2. assert gunzipSync accurately restores original string content compressed with gzipSync
{
  const message = 'The quick brown fox jumps over the lazy dog. 1234567890!@#$%^&*()';
  const input = new TextEncoder().encode(message);
  const compressed = gzipSync(input);
  const decompressed = gunzipSync(compressed);
  const restoredText = new TextDecoder().decode(decompressed);
  assert.strictEqual(restoredText, message, 'decompressed string content must match original input text exactly');
  assert.deepStrictEqual(decompressed, input, 'decompressed bytes must match original input bytes');
}

// 3. assert gunzipSync decompresses empty GZIP payload into an empty Uint8Array
{
  const emptyInput = new Uint8Array(0);
  const compressed = gzipSync(emptyInput);
  const decompressed = gunzipSync(compressed);
  assert.ok(decompressed instanceof Uint8Array, 'gunzipSync must return a Uint8Array for empty payload');
  assert.strictEqual(decompressed.length, 0, 'decompressed empty payload must have length 0');
}

// 4. assert gunzipSync successfully decompresses large repetitive data
{
  const repetitive = new TextEncoder().encode('ABCDEF1234567890'.repeat(500));
  const compressed = gzipSync(repetitive, { level: 9 });
  const decompressed = gunzipSync(compressed);
  assert.deepStrictEqual(decompressed, repetitive, 'large repetitive decompressed data must match original bytes');
  assert.strictEqual(decompressed.length, repetitive.length, 'decompressed length must match original length');
}

// 5. assert gunzipSync throws an error when given invalid or corrupted gzip data
{
  const invalidData = new Uint8Array([0x00, 0x01, 0x02, 0x03, 0x04]);
  assert.throws(
    () => {
      gunzipSync(invalidData);
    },
    /invalid gzip data/i,
    'gunzipSync must throw an error when provided with invalid gzip data'
  );
}

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