nanoid 5.1.16: nanoid

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.nanoid in pkg:npm/nanoid@5.1.16
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/nanoid@5.1.16
Demonstrate these symbols/APIs:
  - nanoid.nanoid

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:faec17fc17536ca7af8f79fe0261ca31c6b3c4359ffa55cd8a72cc0ae4cc00fe","contract":["nanoid generates a 21-character URL-friendly unique string by default","nanoid accepts a custom size parameter to specify the length of the generated string","nanoid generates unique IDs across multiple invocations without collision"],"goal":"verify nanoid.nanoid in pkg:npm/nanoid@5.1.16","kind":"HOW","packages":["pkg:npm/nanoid@5.1.16"],"schemaVersion":1,"symbols":["nanoid.nanoid"]},"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@5.1.16"],"schemaVersion":1,"subject":"pkg:npm/nanoid@5.1.16","symbols":["nanoid.nanoid"],"verifierAdapter":"node-typescript@1"}

import { nanoid } from "nanoid";

/**
 * Generates a random unique ID with default length (21).
 * @returns {string} Generated ID string.
 */
export function generateId() {
  return nanoid();
}

/**
 * Generates a random unique ID with a specified length.
 * @param {number} size - Length of the generated ID.
 * @returns {string} Generated ID string.
 */
export function generateIdWithSize(size) {
  return nanoid(size);
}

export { nanoid };

{
  "name": "sample-nanoid-nanoid",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-nanoid-nanoid",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "nanoid": "5.1.16"
      }
    },
    "node_modules/nanoid": {
      "version": "5.1.16",
      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-5.1.16.tgz",
      "integrity": "sha512-kVrnsrJqMR8+oLJnGEmSWw9BivK5mt7H3FZatVRjrc5wGqFYuBxX1yG7+A7Gi5AefkX6t/oCkizcQgpu0cY1dQ==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/ai"
        }
      ],
      "license": "MIT",
      "bin": {
        "nanoid": "bin/nanoid.js"
      },
      "engines": {
        "node": "^18 || >=20"
      }
    }
  }
}

{
  "name": "sample-nanoid-nanoid",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "description": "verify nanoid.nanoid in pkg:npm/nanoid@5.1.16",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "nanoid": "5.1.16"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify nanoid.nanoid in pkg:npm/nanoid@5.1.16",
  "kind": "HOW",
  "packages": [
    "pkg:npm/nanoid@5.1.16"
  ],
  "symbols": [
    "nanoid.nanoid"
  ]
}

import assert from "node:assert";
import { nanoid } from "nanoid";
import { generateId, generateIdWithSize } from "../index.js";

const URL_ALPHABET_PATTERN = /^[A-Za-z0-9_-]+$/;

function testDefaultId() {
  const id = nanoid();
  assert.strictEqual(typeof id, "string", "nanoid() must return a string");
  assert.strictEqual(id.length, 21, "nanoid() default length must be 21");
  assert.match(id, URL_ALPHABET_PATTERN, "nanoid() must use URL-safe characters");
}

function testCustomSize() {
  const sizes = [1, 5, 10, 32, 64];
  for (const size of sizes) {
    const id = nanoid(size);
    assert.strictEqual(typeof id, "string", `nanoid(${size}) must return a string`);
    assert.strictEqual(id.length, size, `nanoid(${size}) length must be ${size}`);
    assert.match(id, URL_ALPHABET_PATTERN, `nanoid(${size}) must use URL-safe characters`);
  }
}

function testUniqueness() {
  const count = 1000;
  const seen = new Set();
  for (let i = 0; i < count; i++) {
    const id = nanoid();
    assert.strictEqual(seen.has(id), false, `Collision detected: ${id}`);
    seen.add(id);
  }
  assert.strictEqual(seen.size, count, "All generated IDs must be unique");
}

function testHelperFunctions() {
  const id1 = generateId();
  assert.strictEqual(typeof id1, "string");
  assert.strictEqual(id1.length, 21);

  const id2 = generateIdWithSize(12);
  assert.strictEqual(typeof id2, "string");
  assert.strictEqual(id2.length, 12);
}

function run() {
  testDefaultId();
  testCustomSize();
  testUniqueness();
  testHelperFunctions();
  console.log("Contract tests passed successfully.");
}

try {
  run();
  process.exit(0);
} catch (err) {
  console.error("Contract test failed:", err);
  process.exit(1);
}