neo-async 2.6.2: async.map

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 async.map in pkg:npm/neo-async@2.6.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/neo-async@2.6.2
Demonstrate these symbols/APIs:
  - async.map

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:sha256:0724a8efe23675322e47049eada2b4f981c4d1a78ed86bff0df66a3874ec9672","contract":["async.map transforms an array of items in parallel and preserves original item ordering in results","async.map transforms values of an object and returns an array of mapped results","async.map invokes final callback immediately with error when an iteratee fails","async.map returns an empty array when given an empty collection or null","async.map correctly passes item and callback arguments to async iteratee functions across event loop ticks"],"goal":"verify async.map in pkg:npm/neo-async@2.6.2","kind":"HOW","packages":["pkg:npm/neo-async@2.6.2"],"schemaVersion":1,"symbols":["async.map"]},"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/neo-async@2.6.2"],"schemaVersion":1,"subject":"pkg:npm/neo-async@2.6.2","symbols":["async.map"],"verifierAdapter":"node-typescript@1"}

'use strict';

const async = require('neo-async');

function mapItems(collection, iteratee, callback) {
  return async.map(collection, iteratee, callback);
}

module.exports = {
  mapItems,
  map: async.map,
  async
};

{
  "name": "sample-neo-async-map",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-neo-async-map",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "neo-async": "2.6.2"
      }
    },
    "node_modules/neo-async": {
      "version": "2.6.2",
      "resolved": "https://registry.npmjs.org/neo-async/-/neo-async-2.6.2.tgz",
      "integrity": "sha512-Yd3UES5mWCSqR+qNT93S3UoYUkqAZ9lLg8a7g9rimsWmYGK8cVToA4/sF3RrshdyV3sAGMXVUmpMYOw+dLpOuw==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-neo-async-map",
  "version": "1.0.0",
  "private": true,
  "description": "verify async.map in pkg:npm/neo-async@2.6.2",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.cjs"
  },
  "dependencies": {
    "neo-async": "2.6.2"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify async.map in pkg:npm/neo-async@2.6.2",
  "kind": "HOW",
  "packages": [
    "pkg:npm/neo-async@2.6.2"
  ],
  "symbols": [
    "async.map"
  ]
}

'use strict';

const assert = require('assert');
const async = require('neo-async');
const { mapItems } = require('../index.js');

async function testParallelTransformationPreservesOrder() {
  return new Promise((resolve, reject) => {
    const input = [1, 2, 3, 4];
    const delays = { 1: 30, 2: 10, 3: 20, 4: 5 };
    const completionOrder = [];

    async.map(input, (item, cb) => {
      setTimeout(() => {
        completionOrder.push(item);
        cb(null, item * 10);
      }, delays[item]);
    }, (err, results) => {
      if (err) return reject(err);
      try {
        assert.deepStrictEqual(results, [10, 20, 30, 40]);
        assert.deepStrictEqual(completionOrder, [4, 2, 3, 1]);
        resolve();
      } catch (e) {
        reject(e);
      }
    });
  });
}

async function testObjectTransformation() {
  return new Promise((resolve, reject) => {
    const inputObj = { a: 1, b: 2, c: 3 };

    async.map(inputObj, (value, cb) => {
      setImmediate(() => {
        cb(null, value + 100);
      });
    }, (err, results) => {
      if (err) return reject(err);
      try {
        assert.deepStrictEqual(results, [101, 102, 103]);
        resolve();
      } catch (e) {
        reject(e);
      }
    });
  });
}

async function testErrorHaltsExecution() {
  return new Promise((resolve, reject) => {
    const input = [1, 2, 3, 4];
    const testError = new Error('map failed on item 2');

    async.map(input, (item, cb) => {
      if (item === 2) {
        cb(testError);
      } else {
        setTimeout(() => {
          cb(null, item * 2);
        }, 50);
      }
    }, (err, results) => {
      try {
        assert.strictEqual(err, testError);
        assert(Array.isArray(results));
        resolve();
      } catch (e) {
        reject(e);
      }
    });
  });
}

async function testEmptyCollection() {
  return new Promise((resolve, reject) => {
    async.map([], (item, cb) => {
      cb(null, item);
    }, (err, results) => {
      if (err) return reject(err);
      try {
        assert.deepStrictEqual(results, []);
        async.map(null, (item, cb) => cb(null, item), (errNull, resultsNull) => {
          if (errNull) return reject(errNull);
          try {
            assert.deepStrictEqual(resultsNull, []);
            resolve();
          } catch (e) {
            reject(e);
          }
        });
      } catch (e) {
        reject(e);
      }
    });
  });
}

async function testAsynchronousIterateeTicks() {
  return new Promise((resolve, reject) => {
    const input = ['alpha', 'beta', 'gamma'];

    mapItems(input, (item, cb) => {
      process.nextTick(() => {
        cb(null, item.toUpperCase());
      });
    }, (err, results) => {
      if (err) return reject(err);
      try {
        assert.deepStrictEqual(results, ['ALPHA', 'BETA', 'GAMMA']);
        resolve();
      } catch (e) {
        reject(e);
      }
    });
  });
}

async function main() {
  await testParallelTransformationPreservesOrder();
  await testObjectTransformation();
  await testErrorHaltsExecution();
  await testEmptyCollection();
  await testAsynchronousIterateeTicks();
  console.log('All async.map contract assertions passed successfully.');
}

main().catch((err) => {
  console.error('Contract test failed:', err);
  process.exit(1);
});