fflate 0.8.3: deflateSync, gunzipSync, gzipSync

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 pkg:npm/fflate@0.8.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/fflate@0.8.3

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:e9175d714d1ab0f4dbfd4ff686a48e0beebe26004d964bfbce76dcb6ceec4e9e","contract":["strToU8 and strFromU8 convert UTF-8 strings to and from Uint8Array","gzipSync compresses Uint8Array data and gunzipSync decompresses back to original data","zlibSync compresses Uint8Array data and unzlibSync decompresses back to original data","deflateSync compresses raw deflate data and inflateSync restores original data","zipSync creates a valid ZIP archive and unzipSync restores original files and content"],"goal":"verify pkg:npm/fflate@0.8.3","kind":"HOW","packages":["pkg:npm/fflate@0.8.3"],"schemaVersion":1,"symbols":["deflateSync","gunzipSync","gzipSync","inflateSync","strFromU8","strToU8","unzipSync","unzlibSync","zipSync","zlibSync"]},"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":["deflateSync","gunzipSync","gzipSync","inflateSync","strFromU8","strToU8","unzipSync","unzlibSync","zipSync","zlibSync"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-fflate",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fflate",
      "version": "1.0.0",
      "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",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification for pkg:npm/fflate@0.8.3",
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "fflate": "0.8.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/fflate@0.8.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/fflate@0.8.3"
  ],
  "symbols": [
    "deflateSync",
    "gunzipSync",
    "gzipSync",
    "inflateSync",
    "strFromU8",
    "strToU8",
    "unzipSync",
    "unzlibSync",
    "zipSync",
    "zlibSync"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "esm",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import assert from 'node:assert/strict';
import {
  strToU8,
  strFromU8,
  gzipSync,
  gunzipSync,
  zlibSync,
  unzlibSync,
  deflateSync,
  inflateSync,
  zipSync,
  unzipSync
} from 'fflate';

// 1. strToU8 and strFromU8 convert UTF-8 strings to and from Uint8Array
{
  const text = 'Hello, fflate compression test!';
  const u8 = strToU8(text);
  assert.ok(u8 instanceof Uint8Array);
  assert.equal(strFromU8(u8), text);
}

// 2. gzipSync compresses Uint8Array data and gunzipSync decompresses back to original data
{
  const text = 'Data payload to be compressed with gzip format.';
  const u8 = strToU8(text);
  const compressed = gzipSync(u8);
  assert.ok(compressed instanceof Uint8Array);
  assert.ok(compressed.length > 0);
  const decompressed = gunzipSync(compressed);
  assert.deepEqual(decompressed, u8);
  assert.equal(strFromU8(decompressed), text);
}

// 3. zlibSync compresses Uint8Array data and unzlibSync decompresses back to original data
{
  const text = 'Data payload to be compressed with zlib format.';
  const u8 = strToU8(text);
  const compressed = zlibSync(u8);
  assert.ok(compressed instanceof Uint8Array);
  assert.ok(compressed.length > 0);
  const decompressed = unzlibSync(compressed);
  assert.deepEqual(decompressed, u8);
  assert.equal(strFromU8(decompressed), text);
}

// 4. deflateSync compresses raw deflate data and inflateSync restores original data
{
  const text = 'Raw deflate payload testing deflation and inflation.';
  const u8 = strToU8(text);
  const deflated = deflateSync(u8);
  assert.ok(deflated instanceof Uint8Array);
  assert.ok(deflated.length > 0);
  const inflated = inflateSync(deflated);
  assert.deepEqual(inflated, u8);
  assert.equal(strFromU8(inflated), text);
}

// 5. zipSync creates a valid ZIP archive and unzipSync restores original files and content
{
  const files = {
    'sample.txt': strToU8('file content 1'),
    'subfolder/data.json': strToU8('{"valid":true}')
  };
  const zipped = zipSync(files);
  assert.ok(zipped instanceof Uint8Array);
  assert.ok(zipped.length > 0);
  const unzipped = unzipSync(zipped);
  assert.ok(unzipped['sample.txt']);
  assert.ok(unzipped['subfolder/data.json']);
  assert.equal(strFromU8(unzipped['sample.txt']), 'file content 1');
  assert.equal(strFromU8(unzipped['subfolder/data.json']), '{"valid":true}');
}

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