universalify 2.0.1

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/universalify@2.0.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/universalify@2.0.1
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:bd6cb9d03c70d931eabeb5b873e98e2f0d9b2ce6337dcc51fef9bb6409fd8f72","constraints":{"executionContext":"node"},"contract":["universalify exports fromCallback and fromPromise helper functions","universalify.fromCallback converts a callback-taking function to return a promise when no callback argument is provided","universalify.fromCallback executes with standard error-first callback when a callback argument is provided","universalify.fromCallback rejects promise on callback error","universalify.fromPromise converts a promise-returning function to support standard error-first callback","universalify.fromPromise returns a promise when invoked without a callback argument","universalify.fromPromise delivers rejection to callback as error argument","universalify preserves function name and this context across conversions"],"goal":"verify pkg:npm/universalify@2.0.1","kind":"HOW","packages":["pkg:npm/universalify@2.0.1"],"schemaVersion":1},"contractCommand":["node","test/contract.js"],"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/universalify@2.0.1"],"schemaVersion":1,"subject":"pkg:npm/universalify@2.0.1","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-universalify",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-universalify",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "universalify": "2.0.1"
      }
    },
    "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-universalify",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for universalify",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "universalify": "2.0.1"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/universalify@2.0.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/universalify@2.0.1"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const universalify = require('universalify');

function makeUniversalCallback(fn) {
  return universalify.fromCallback(fn);
}

function makeUniversalPromise(fn) {
  return universalify.fromPromise(fn);
}

module.exports = {
  makeUniversalCallback,
  makeUniversalPromise
};

const assert = require('node:assert');
const universalify = require('universalify');
const { makeUniversalCallback, makeUniversalPromise } = require('../src/index.js');

async function runTests() {
  // 1. universalify exports fromCallback and fromPromise helper functions
  assert.strictEqual(typeof universalify.fromCallback, 'function', 'fromCallback should be a function');
  assert.strictEqual(typeof universalify.fromPromise, 'function', 'fromPromise should be a function');

  // 2. universalify.fromCallback converts a callback-taking function to return a promise when no callback argument is provided
  function asyncAdd(a, b, cb) {
    setTimeout(() => {
      cb(null, a + b);
    }, 10);
  }
  const uAdd = universalify.fromCallback(asyncAdd);
  const promiseResult = await uAdd(2, 3);
  assert.strictEqual(promiseResult, 5, 'Promise resolution should return sum');

  const wrapperAdd = makeUniversalCallback(asyncAdd);
  const wrapperResult = await wrapperAdd(10, 20);
  assert.strictEqual(wrapperResult, 30, 'Wrapper promise resolution should return sum');

  // 3. universalify.fromCallback executes with standard error-first callback when a callback argument is provided
  let callbackCalled = false;
  await new Promise((resolve, reject) => {
    uAdd(4, 6, (err, res) => {
      if (err) return reject(err);
      callbackCalled = true;
      assert.strictEqual(res, 10, 'Callback should receive result');
      resolve();
    });
  });
  assert.strictEqual(callbackCalled, true, 'Callback should have been called');

  // 4. universalify.fromCallback rejects promise on callback error
  function failingAsync(cb) {
    setTimeout(() => {
      cb(new Error('callback failed'));
    }, 10);
  }
  const uFail = universalify.fromCallback(failingAsync);
  await assert.rejects(
    async () => {
      await uFail();
    },
    {
      name: 'Error',
      message: 'callback failed'
    }
  );

  let failCallbackCalled = false;
  await new Promise((resolve) => {
    uFail((err, res) => {
      failCallbackCalled = true;
      assert.strictEqual(err instanceof Error, true);
      assert.strictEqual(err.message, 'callback failed');
      resolve();
    });
  });
  assert.strictEqual(failCallbackCalled, true, 'Error callback should have been called');

  // 5. universalify.fromPromise converts a promise-returning function to support standard error-first callback
  async function promiseMultiply(a, b) {
    return a * b;
  }
  const uMul = universalify.fromPromise(promiseMultiply);
  let mulCallbackCalled = false;
  await new Promise((resolve, reject) => {
    uMul(3, 7, (err, res) => {
      if (err) return reject(err);
      mulCallbackCalled = true;
      assert.strictEqual(res, 21, 'Callback should receive product');
      resolve();
    });
  });
  assert.strictEqual(mulCallbackCalled, true, 'Multiply callback should have been called');

  // 6. universalify.fromPromise returns a promise when invoked without a callback argument
  const mulPromiseResult = await uMul(4, 5);
  assert.strictEqual(mulPromiseResult, 20, 'Promise mode should return product');

  const wrapperMul = makeUniversalPromise(promiseMultiply);
  const wrapperMulResult = await wrapperMul(5, 5);
  assert.strictEqual(wrapperMulResult, 25, 'Wrapper promise mode should return product');

  // 7. universalify.fromPromise delivers rejection to callback as error argument
  async function promiseRejection() {
    throw new Error('promise rejected');
  }
  const uReject = universalify.fromPromise(promiseRejection);
  let rejectCallbackCalled = false;
  await new Promise((resolve) => {
    uReject((err, res) => {
      rejectCallbackCalled = true;
      assert.strictEqual(err instanceof Error, true);
      assert.strictEqual(err.message, 'promise rejected');
      resolve();
    });
  });
  assert.strictEqual(rejectCallbackCalled, true, 'Rejection callback should have been called');

  await assert.rejects(
    async () => {
      await uReject();
    },
    {
      name: 'Error',
      message: 'promise rejected'
    }
  );

  // 8. universalify preserves function name and this context across conversions
  function namedFunc(cb) {
    cb(null, this.value);
  }
  const uNamed = universalify.fromCallback(namedFunc);
  assert.strictEqual(uNamed.name, 'namedFunc', 'Function name should be preserved');

  const contextObj = {
    value: 'context-test',
    run: uNamed
  };
  const contextResult = await contextObj.run();
  assert.strictEqual(contextResult, 'context-test', 'this context should be preserved in promise mode');

  console.log('All universalify@2.0.1 contract assertions passed.');
}

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