どこでもJavaScriptを使おう

// server.mjs
import { createServer } from 'node:http';

const server = createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello World!\n');
});

// starts a simple http server locally on port 3000
server.listen(3000, '127.0.0.1', () => {
  console.log('Listening on 127.0.0.1:3000');
});

// run with `node server.mjs`

// tests.mjs
import assert from 'node:assert';
import test from 'node:test';

test('that 1 is equal 1', () => {
  assert.strictEqual(1, 1);
});

test('that throws as 1 is not equal 2', () => {
  // throws an exception because 1 != 2
  assert.strictEqual(1, 2);
});

// run with `node tests.mjs`

// crypto.mjs
import { createHash } from 'node:crypto';
import { readFile } from 'node:fs/promises';

const hasher = createHash('sha1');

hasher.setEncoding('hex');
// ensure you have a `package.json` file for this test!
hasher.write(await readFile('package.json'));
hasher.end();

const fileHash = hasher.read();

// run with `node crypto.mjs`

// streams.mjs
import { createReadStream, createWriteStream } from 'node:fs';
import { pipeline } from 'node:stream/promises';
import { createGzip } from 'node:zlib';

// ensure you have a `package.json` file for this test!
await pipeline(
  createReadStream('package.json'),
  createGzip(),
  createWriteStream('package.json.gz')
);


// run with `node streams.mjs`

// threads.mjs
import { Worker, isMainThread,
  workerData, parentPort } from 'node:worker_threads';

if (isMainThread) {
  const data = 'some data';
  const worker = new Worker(import.meta.filename, { workerData: data });
  worker.on('message', msg => console.log('Reply from Thread:', msg));
} else {
  const source = workerData;
  parentPort.postMessage(btoa(source.toUpperCase()));
}

// run with `node threads.mjs`