nanoid 3.3.17: async

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 nanoid/async in pkg:npm/nanoid@3.3.17
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/nanoid@3.3.17
Demonstrate these symbols/APIs:
  - nanoid/async

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:sha256:325c92f4249ab162f353e2df67d3263bb2495807f0584af812c1fc606ab1db4d","contract":["import nanoid, customAlphabet, and random from nanoid/async in ESM","assert async nanoid resolves to 21 URL-safe characters","assert async nanoid with custom size resolves to specified character count","assert async customAlphabet returns generator that resolves to custom alphabet characters and length","assert async random resolves to Uint8Array of requested byte size","assert concurrently generated async nanoid IDs are unique"],"goal":"verify nanoid/async in pkg:npm/nanoid@3.3.17","kind":"HOW","packages":["pkg:npm/nanoid@3.3.17"],"schemaVersion":1,"symbols":["nanoid/async"]},"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/nanoid@3.3.17"],"schemaVersion":1,"subject":"pkg:npm/nanoid@3.3.17","symbols":["nanoid/async"],"verifierAdapter":"node-typescript@1"}

{
  "name": "csx-sample-nanoid-async",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "csx-sample-nanoid-async",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "nanoid": "3.3.17"
      }
    },
    "node_modules/nanoid": {
      "version": "3.3.17",
      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.17.tgz",
      "integrity": "sha512-xQLf0A3HOMlgHq0n247/LRuAOYmB7dXJ/DvAxGvsSBij45XtBSmQycu+F8ODbHwns/XyFZagyL1+J0Offw1E0g==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/ai"
        }
      ],
      "license": "MIT",
      "bin": {
        "nanoid": "bin/nanoid.cjs"
      },
      "engines": {
        "node": "^10 || ^12 || ^13.7 || ^14 || >=15.0.1"
      }
    }
  }
}

{
  "name": "csx-sample-nanoid-async",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "nanoid": "3.3.17"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify nanoid/async in pkg:npm/nanoid@3.3.17",
  "kind": "HOW",
  "packages": [
    "pkg:npm/nanoid@3.3.17"
  ],
  "symbols": [
    "nanoid/async"
  ]
}

import { nanoid, customAlphabet, random } from 'nanoid/async';

export async function generateAsyncId(size) {
  return size ? nanoid(size) : nanoid();
}

export function createAsyncCustomGenerator(alphabet, size) {
  return customAlphabet(alphabet, size);
}

export async function generateAsyncRandomBytes(bytes) {
  return random(bytes);
}

export { nanoid, customAlphabet, random };

import assert from 'node:assert/strict';
import {
  generateAsyncId,
  createAsyncCustomGenerator,
  generateAsyncRandomBytes,
  nanoid,
  customAlphabet,
  random
} from '../src/index.js';

// 1. ESM exports are functions
assert.equal(typeof nanoid, 'function', 'nanoid should be an async function');
assert.equal(typeof customAlphabet, 'function', 'customAlphabet should be a function returning an async generator');
assert.equal(typeof random, 'function', 'random should be an async function');

// 2. Default async nanoid produces 21 URL-safe characters
const defaultId = await generateAsyncId();
assert.equal(typeof defaultId, 'string', 'defaultId should be a string');
assert.equal(defaultId.length, 21, 'default nanoid should have length 21');
assert.match(defaultId, /^[A-Za-z0-9_-]{21}$/, 'default nanoid should only contain URL-safe chars');

// 3. Async nanoid with custom length produces specified character count
const customLengthId = await generateAsyncId(32);
assert.equal(customLengthId.length, 32, 'nanoid(32) should have length 32');
assert.match(customLengthId, /^[A-Za-z0-9_-]{32}$/, 'nanoid(32) should only contain URL-safe chars');

// 4. Custom alphabet generator produces IDs matching alphabet and size
const hexGenerator = createAsyncCustomGenerator('0123456789abcdef', 16);
const hexId = await hexGenerator();
assert.equal(hexId.length, 16, 'customAlphabet id should have length 16');
assert.match(hexId, /^[0-9a-f]{16}$/, 'customAlphabet id should only contain hex chars');

const customSizeHexId = await hexGenerator(8);
assert.equal(customSizeHexId.length, 8, 'customAlphabet id with override size should have length 8');
assert.match(customSizeHexId, /^[0-9a-f]{8}$/, 'customAlphabet id with override size should only contain hex chars');

// 5. Async random produces Uint8Array of requested byte size
const randomBytes = await generateAsyncRandomBytes(16);
assert.ok(randomBytes instanceof Uint8Array, 'random should resolve to a Uint8Array');
assert.equal(randomBytes.length, 16, 'random(16) should have length 16');

// 6. Concurrent generation produces unique IDs
const idPromises = Array.from({ length: 500 }, () => generateAsyncId());
const ids = await Promise.all(idPromises);
const uniqueIds = new Set(ids);
assert.equal(uniqueIds.size, 500, '500 concurrently generated nanoids should all be unique');

console.log('CONTRACT PASS: nanoid/async verified successfully');