fs-extra 9.1.0: outputFile

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 fs-extra.outputFile in pkg:npm/fs-extra@9.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/fs-extra@9.1.0
Demonstrate these symbols/APIs:
  - fs-extra.outputFile
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:421488946c65e34bc74ed83af7333e42878e15b27ae7e27d546cd7d6e7e83e3a","constraints":{"executionContext":"node"},"contract":["outputFile writes string data asynchronously creating parent directories if they do not exist","outputFile writes Buffer data asynchronously creating parent directories if they do not exist","outputFile overwrites existing file content when called on an existing file path","outputFileSync synchronously writes data creating parent directories if they do not exist","outputFile supports custom file encoding options"],"goal":"verify fs-extra.outputFile in pkg:npm/fs-extra@9.1.0","kind":"HOW","packages":["pkg:npm/fs-extra@9.1.0"],"schemaVersion":1,"symbols":["fs-extra.outputFile"]},"contractCommand":["node","test/contract.cjs"],"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/fs-extra@9.1.0"],"schemaVersion":1,"subject":"pkg:npm/fs-extra@9.1.0","symbols":["fs-extra.outputFile"],"verifierAdapter":"node-typescript@1"}

'use strict';

const fs = require('fs-extra');

async function writeOutputFile(filePath, data, options) {
  return await fs.outputFile(filePath, data, options);
}

function writeOutputFileSync(filePath, data, options) {
  return fs.outputFileSync(filePath, data, options);
}

module.exports = {
  writeOutputFile,
  writeOutputFileSync,
  outputFile: fs.outputFile,
  outputFileSync: fs.outputFileSync
};

{
  "name": "sample-fs-extra-outputfile",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fs-extra-outputfile",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "fs-extra": "9.1.0"
      }
    },
    "node_modules/at-least-node": {
      "version": "1.0.0",
      "resolved": "https://registry.npmjs.org/at-least-node/-/at-least-node-1.0.0.tgz",
      "integrity": "sha512-+q/t7Ekv1EDY2l6Gda6LLiX14rU9TV20Wa3ofeQmwPFZbOMo9DXrLbOjFaaclkXKWidIaopwAObQDqwWtGUjqg==",
      "license": "ISC",
      "engines": {
        "node": ">= 4.0.0"
      }
    },
    "node_modules/fs-extra": {
      "version": "9.1.0",
      "resolved": "https://registry.npmjs.org/fs-extra/-/fs-extra-9.1.0.tgz",
      "integrity": "sha512-hcg3ZmepS30/7BSFqRvoo3DOMQu7IjqxO5nCDt+zM9XWjb33Wg7ziNT+Qvqbuc3+gWpzO02JubVyk2G4Zvo1OQ==",
      "license": "MIT",
      "dependencies": {
        "at-least-node": "^1.0.0",
        "graceful-fs": "^4.2.0",
        "jsonfile": "^6.0.1",
        "universalify": "^2.0.0"
      },
      "engines": {
        "node": ">=10"
      }
    },
    "node_modules/graceful-fs": {
      "version": "4.2.11",
      "resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.2.11.tgz",
      "integrity": "sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ==",
      "license": "ISC"
    },
    "node_modules/jsonfile": {
      "version": "6.2.1",
      "resolved": "https://registry.npmjs.org/jsonfile/-/jsonfile-6.2.1.tgz",
      "integrity": "sha512-zwOTdL3rFQ/lRdBnntKVOX6k5cKJwEc1HdilT71BWEu7J41gXIB2MRp+vxduPSwZJPWBxEzv4yH1wYLJGUHX4Q==",
      "license": "MIT",
      "dependencies": {
        "universalify": "^2.0.0"
      },
      "optionalDependencies": {
        "graceful-fs": "^4.1.6"
      }
    },
    "node_modules/universalify": {
      "version": "2.0.1",
      "resolved": "https://registry.npmjs.org/universalify/-/universalify-2.0.1.tgz",
      "integrity": "sha512-gptHNQghINnc/vTGIk0SOFGFNXw7JVrlRUtConJRlvaw6DuX0wO5Jeko9sWrMBhh+PsYAZ7oXAiOnf/UKogyiw==",
      "license": "MIT",
      "engines": {
        "node": ">= 10.0.0"
      }
    }
  }
}

{
  "name": "sample-fs-extra-outputfile",
  "version": "1.0.0",
  "private": true,
  "description": "verify fs-extra.outputFile in pkg:npm/fs-extra@9.1.0",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.cjs"
  },
  "dependencies": {
    "fs-extra": "9.1.0"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify fs-extra.outputFile in pkg:npm/fs-extra@9.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/fs-extra@9.1.0"
  ],
  "symbols": [
    "fs-extra.outputFile"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const assert = require('node:assert/strict');
const fs = require('fs');
const path = require('path');
const os = require('os');
const fse = require('fs-extra');
const {
  writeOutputFile,
  writeOutputFileSync,
  outputFile,
  outputFileSync
} = require('../index.js');

async function runTests() {
  const tmpBase = fs.mkdtempSync(path.join(os.tmpdir(), 'fse-outputfile-contract-'));

  try {
    // 1. outputFile writes string data asynchronously creating parent directories if they do not exist
    const nestedStringFile = path.join(tmpBase, 'nested', 'string', 'dir', 'hello.txt');
    assert.equal(fs.existsSync(nestedStringFile), false, 'target file must not exist prior to outputFile');
    assert.equal(fs.existsSync(path.dirname(nestedStringFile)), false, 'parent directory must not exist');

    await writeOutputFile(nestedStringFile, 'hello world');
    assert.equal(fs.existsSync(nestedStringFile), true, 'nestedStringFile must exist after writeOutputFile');
    assert.equal(fs.readFileSync(nestedStringFile, 'utf8'), 'hello world', 'content must match written string');

    // Direct fs-extra.outputFile call
    const directAsyncFile = path.join(tmpBase, 'direct', 'async', 'file.txt');
    await outputFile(directAsyncFile, 'direct async content');
    assert.equal(fs.existsSync(directAsyncFile), true, 'directAsyncFile must exist after outputFile');
    assert.equal(fs.readFileSync(directAsyncFile, 'utf8'), 'direct async content', 'content must match');

    // 2. outputFile writes Buffer data asynchronously creating parent directories if they do not exist
    const nestedBufferFile = path.join(tmpBase, 'nested', 'buffer', 'dir', 'binary.bin');
    const bufferData = Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]);
    await writeOutputFile(nestedBufferFile, bufferData);
    assert.equal(fs.existsSync(nestedBufferFile), true, 'nestedBufferFile must exist');
    const readBuffer = fs.readFileSync(nestedBufferFile);
    assert.equal(Buffer.compare(readBuffer, bufferData), 0, 'binary content must match');

    // 3. outputFile overwrites existing file content when called on an existing file path
    await writeOutputFile(nestedStringFile, 'updated content');
    assert.equal(fs.readFileSync(nestedStringFile, 'utf8'), 'updated content', 'content must be overwritten');

    // 4. outputFileSync synchronously writes data creating parent directories if they do not exist
    const nestedSyncFile = path.join(tmpBase, 'nested', 'sync', 'dir', 'sync.txt');
    assert.equal(fs.existsSync(nestedSyncFile), false, 'target sync file must not exist');
    writeOutputFileSync(nestedSyncFile, 'sync content');
    assert.equal(fs.existsSync(nestedSyncFile), true, 'nestedSyncFile must exist after writeOutputFileSync');
    assert.equal(fs.readFileSync(nestedSyncFile, 'utf8'), 'sync content', 'sync content must match');

    // Direct outputFileSync call
    const directSyncFile = path.join(tmpBase, 'direct', 'sync', 'file.txt');
    outputFileSync(directSyncFile, 'direct sync content');
    assert.equal(fs.existsSync(directSyncFile), true, 'directSyncFile must exist after outputFileSync');
    assert.equal(fs.readFileSync(directSyncFile, 'utf8'), 'direct sync content', 'content must match');

    // 5. outputFile supports custom file encoding options
    const customEncodingFile = path.join(tmpBase, 'nested', 'encoding', 'encoded.txt');
    await outputFile(customEncodingFile, 'base64 text', { encoding: 'utf8' });
    assert.equal(fs.readFileSync(customEncodingFile, 'utf8'), 'base64 text');

    console.log('Contract tests passed successfully.');
  } finally {
    try {
      fs.rmSync(tmpBase, { recursive: true, force: true });
    } catch {
      // ignore cleanup errors
    }
  }
}

runTests().catch((err) => {
  console.error(err);
  process.exit(1);
});