Node.js 19正式發布，聊聊它的 6 大功能！

const http = require('node:http');
console.log(http.globalAgent);
const https = require('node:https');
console.log(https.globalAgent);

const { subtle } = globalThis.crypto;

(async function() {

  const key = await subtle.generateKey({
    name: 'HMAC',
    hash: 'SHA-256',
    length: 256
  }, true, ['sign', 'verify']);

  console.log('key =', key);

  const enc = new TextEncoder();
  const message = enc.encode('I love cupcakes');

  console.log('message =', message);

  const digest = await subtle.sign({
    name: 'HMAC'
  }, key, message);

  console.log('digest =', digest);

})();

% node server
key = CryptoKey {
  type: 'secret',
  extractable: true,
  algorithm: { name: 'HMAC', length: 256, hash: [Object] },
  usages: [ 'sign', 'verify' ]
}
message = Uint8Array(15) [   73, 32, 108, 111, 118,  101, 32,  99, 117, 112,   99, 97, 107, 101, 115]
digest = ArrayBuffer {
  [Uint8Contents]: <30 01 7a 5c d9 e2 82 55 6b 55 90 4f 1d de 36 d7 89 dd fb fb 1a 9e a0 cc 5d d8 49 13 38 2f d1 bc>,
  byteLength: 32
}

git clone https://github.com/nodejs/loaders-test.git

% cd loaders-test/commonjs-extension-resolution-loader

% yarn install

import { version } from 'process';

import { valueInFile } from './file';
import { valueInFolderIndex } from './folder';

console.log(valueInFile);
console.log(valueInFolderIndex);

import { isBuiltin } from 'node:module';
import { dirname } from 'node:path';
import { cwd } from 'node:process';
import { fileURLToPath, pathToFileURL } from 'node:url';
import { promisify } from 'node:util';

import resolveCallback from 'resolve/async.js';

const resolveAsync = promisify(resolveCallback);

const baseURL = pathToFileURL(cwd() + '/').href;


export async function resolve(specifier, context, next) {
  const { parentURL = baseURL } = context;

  if (isBuiltin(specifier)) {
    return next(specifier, context);
  }

  // `resolveAsync` works with paths, not URLs
  if (specifier.startsWith('file://')) {
    specifier = fileURLToPath(specifier);
  }
  const parentPath = fileURLToPath(parentURL);

  let url;
  try {
    const resolution = await resolveAsync(specifier, {
      basedir: dirname(parentPath),
      // For whatever reason, --experimental-specifier-resolution=node doesn't search for .mjs extensions
      // but it does search for index.mjs files within directories
      extensions: ['.js', '.json', '.node', '.mjs'],
    });
    url = pathToFileURL(resolution).href;
  } catch (error) {
    if (error.code === 'MODULE_NOT_FOUND') {
      // Match Node's error code
      error.code = 'ERR_MODULE_NOT_FOUND';
    }
    throw error;
  }

  return next(url, context);
}

% node --loader=./loader.js test/basic-fixtures/index  
(node:56149) ExperimentalWarning: Custom ESM Loaders is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
hello from file.js

Intl.NumberFormat(locales, options)

const number = 123456.789;

console.log(new Intl.NumberFormat('de-DE', { style: 'currency', currency: 'EUR' }).format(number));
console.log(new Intl.NumberFormat('ja-JP', { style: 'currency', currency: 'JPY' }).format(number));
console.log(new Intl.NumberFormat('ar-SA', { style: 'currency', currency: 'EGP' }).format(number));
console.log(new Intl.NumberFormat('zh-CN', { style: 'currency', currency: 'CNY' }).format(number));

const express = require("express");
const path = require("path");
const app = express();
app.use(express.static(path.join(__dirname, "../build")));

app.listen(8080, () =>
  console.log("Express server is running on localhost:8080")
);

% node --watch server
(node:67643) ExperimentalWarning: Watch mode is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
Express server is running on localhost:8080