fflate 0.8.3: unzlibSync

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.unzlibSync 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.unzlibSync

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:sha256:8bf83c57660dfb1bfee010e4da6f595143d3f5f6bc1e372c761d298cde25597e","contract":["fflate.unzlibSync is exported as a function","fflate.unzlibSync decompresses valid zlib data to the original byte sequence","fflate.unzlibSync decompresses empty zlib payload to empty Uint8Array","fflate.unzlibSync writes decompressed data into an optional pre-allocated output buffer view","fflate.unzlibSync throws an error when provided invalid or corrupted zlib data","module index wrapper decompressZlibSync matches fflate.unzlibSync output"],"goal":"verify fflate.unzlibSync in pkg:npm/fflate@0.8.3","kind":"HOW","packages":["pkg:npm/fflate@0.8.3"],"schemaVersion":1,"symbols":["fflate.unzlibSync"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/fflate@0.8.3"],"schemaVersion":1,"subject":"pkg:npm/fflate@0.8.3","symbols":["fflate.unzlibSync"],"verifierAdapter":"node-typescript@1"}

import * as fflate from 'fflate';

export const unzlibSync = fflate.unzlibSync;
export const zlibSync = fflate.zlibSync;

/**
 * Synchronously decompresses zlib-compressed data.
 *
 * @param {Uint8Array} data - The compressed zlib byte array.
 * @param {object} [opts] - Optional decompression options.
 * @returns {Uint8Array} Decompressed byte array.
 */
export function decompressZlibSync(data, opts) {
  return fflate.unzlibSync(data, opts);
}

export default fflate;

{
  "name": "sample-fflate-unzlib-sync",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fflate-unzlib-sync",
      "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-unzlib-sync",
  "version": "1.0.0",
  "type": "module",
  "main": "index.mjs",
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "fflate": "0.8.3"
  }
}

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

import assert from 'node:assert/strict';
import * as fflate from 'fflate';
import { unzlibSync, decompressZlibSync } from '../index.mjs';

// 1. fflate.unzlibSync is exported as a function
assert.equal(typeof fflate.unzlibSync, 'function');
assert.equal(typeof unzlibSync, 'function');
assert.equal(typeof decompressZlibSync, 'function');

// 2. fflate.unzlibSync decompresses valid zlib data to the original byte sequence
const sampleText = 'CodeSampleX contract verification: fflate.unzlibSync decompressing zlib stream payload.';
const sampleBytes = new TextEncoder().encode(sampleText);
const compressed = fflate.zlibSync(sampleBytes);
assert(compressed instanceof Uint8Array);
assert(compressed.length > 0);

const decompressed = fflate.unzlibSync(compressed);
assert(decompressed instanceof Uint8Array);
assert.equal(new TextDecoder().decode(decompressed), sampleText);

// 3. fflate.unzlibSync decompresses empty zlib payload to empty Uint8Array
const emptyBytes = new Uint8Array(0);
const compressedEmpty = fflate.zlibSync(emptyBytes);
const decompressedEmpty = fflate.unzlibSync(compressedEmpty);
assert(decompressedEmpty instanceof Uint8Array);
assert.equal(decompressedEmpty.length, 0);

// 4. fflate.unzlibSync writes decompressed data into an optional pre-allocated output buffer view
const preAllocated = new Uint8Array(decompressed.length + 32);
const decompressedPreAllocated = fflate.unzlibSync(compressed, { out: preAllocated });
assert.equal(decompressedPreAllocated.buffer, preAllocated.buffer);
assert.equal(decompressedPreAllocated.length, decompressed.length);
assert.equal(new TextDecoder().decode(decompressedPreAllocated), sampleText);

// 5. fflate.unzlibSync throws an error when provided invalid or corrupted zlib data
assert.throws(
  () => {
    fflate.unzlibSync(new Uint8Array([0xde, 0xad, 0xbe, 0xef, 0x00, 0x11, 0x22, 0x33]));
  },
  Error
);

// 6. module index wrapper decompressZlibSync matches fflate.unzlibSync output
const wrapperDecompressed = decompressZlibSync(compressed);
assert.deepEqual(wrapperDecompressed, decompressed);

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