Node.js v22 & Bun v1.1 Runtime APIs

Node.js & Bun Runtime APIs

@innovatorved/code-lab executes JavaScript and TypeScript inside an isolated Web Worker sandbox. Code executes on the browser's native JavaScript JIT at full hardware speed (~5 ms startup).

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1. Node.js Built-In Modules (24 Modules)

The following Node.js built-ins are shimmed in pure JavaScript without external dependencies:

Module	Key Methods & Classes Supported
fs & node:fs	readFileSync, writeFileSync, appendFileSync, readdirSync, statSync, lstatSync, existsSync, mkdirSync, rmdirSync, rmSync, unlinkSync, renameSync, truncateSync, openSync, readSync, writeSync, closeSync, fsyncSync, fstatSync, createReadStream, createWriteStream.
fs/promises	Full promise-based async filesystem: readFile, writeFile, appendFile, readdir, stat, lstat, mkdir, unlink, rm, rename, open (with FileHandle).
http & node:http	In-memory loopback HTTP server and client: createServer, request, get, Agent, Server. Registers virtual listening ports (:3000, :8080) that can be reached via curl and fetch().
net & node:net	In-memory virtual TCP loopback: createServer, connect, createConnection, Socket, Server, isIP. Used for custom binary RPC and Redis protocol engines.
stream & node:stream	Readable, Writable, Duplex, Transform, PassThrough, pipeline, finished. Fully compatible with async iterators (for await (const chunk of stream)).
events & node:events	Complete EventEmitter with on, once, emit, removeListener, listenerCount, prependListener.
crypto & node:crypto	Synchronous pure-JS implementations: createHash('sha256' | 'md5'), createHmac('sha256', key), timingSafeEqual, randomUUID, randomBytes.
zlib & node:zlib	IEEE 802.3 crc32(buffer) implementation matching POSIX and gzip specs.
path & node:path	join, resolve, dirname, basename, extname, sep, delimiter, isAbsolute, normalize.
os & node:os	tmpdir(), platform(), arch(), homedir(), hostname(), EOL.
buffer	Full Node Buffer class: Buffer.from, Buffer.alloc, Buffer.concat, Buffer.byteLength, .readUInt32BE, .writeUInt32BE, .readBigUInt64BE, .toString('utf8'|'hex'|'base64'|'base64url'), .subarray.
util & node:util	format (printf-style %s, %d, %j), inspect, promisify, callbackify, inherits, types.
url & node:url	Standard URL, URLSearchParams, fileURLToPath, pathToFileURL.
querystring	parse, stringify, escape, unescape.
timers & timers/promises	setTimeout, clearTimeout, setInterval, clearInterval, setImmediate, clearImmediate, and setTimeout(ms) promise.
perf_hooks	performance.now(), performance.mark(), performance.measure().
assert & node:assert/strict	ok, equal, strictEqual, deepStrictEqual, notStrictEqual, throws, rejects, match, fail.
node:test	Structured test harness with test(name, fn), subtests, assertions, and per-test timing capture.
process	process.env, process.argv, process.cwd(), process.uptime(), process.memoryUsage(), process.nextTick(), process.stdout.write().
console	log, info, warn, error, table (ASCII tables), dir, time / timeEnd, count, group / groupEnd, trace.

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2. Bun Runtime APIs

CodeLab supports native TypeScript execution and implements Bun-standard APIs:

Bun.serve({ port, fetch, routes })

Start high-performance HTTP servers directly in the browser:

const server = Bun.serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);
    if (url.pathname === '/health') {
      return new Response(JSON.stringify({ status: 'ok' }), {
        headers: { 'Content-Type': 'application/json' }
      });
    }
    return new Response('Not Found', { status: 404 });
  }
});

Bun.file(path) & Bun.write(path, data)

Read and write virtual files with Web standard streams and blobs:

// Write file
await Bun.write('config.json', JSON.stringify({ rateLimit: 100 }));

// Read file
const file = Bun.file('config.json');
const data = await file.json();
console.log(data.rateLimit); // 100

Additional Bun.* Utilities

• Bun.sleep(ms): Promise that resolves after ms milliseconds.
• Bun.hash(data): Fast 64-bit non-cryptographic hash.
• Bun.deepEquals(a, b): Deep structural equality check.
• Bun.version: Current Bun compatibility version string ("1.1.20").

bun:test

Standard Jest / Vitest-compatible test assertions:

import { describe, test, it, expect, beforeEach } from 'bun:test';

describe('Consistent Hash Ring', () => {
  test('distributes keys evenly', () => {
    expect(ring.getNode('user:101')).toBe('node-a');
    expect([1, 2, 3]).toContain(2);
    expect(() => ring.removeNode('nonexistent')).toThrow();
  });
});

bun:sqlite

In-memory SQLite emulator for system design challenges:

import { Database } from 'bun:sqlite';

const db = new Database(':memory:');
db.run('CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT);');
db.run('INSERT INTO users (name) VALUES (?), (?);', ['Alice', 'Bob']);

const users = db.query('SELECT * FROM users;').all();
console.log(users);

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3. Package Management (npm & bun add)

CodeLab resolves external bare specifiers (import lodash from 'lodash' or require('zod')) on the fly:

1. Terminal Command: Run npm install <pkg> or bun add <pkg> in the integrated terminal:

   bun add zod
   bun add nanoid

2. Auto-Fetch: CodeLab fetches pre-bundled ESM/CJS builds from esm.sh or cdn.jsdelivr.net and writes them into /workspace/node_modules/<pkg>.
3. package.json Sync: CodeLab automatically adds the package to dependencies in /workspace/package.json and updates the file tree.