SOURCE

async function logInOrder(urls) {
  // 并发读取远程URL
  const textPromises = urls.map(async url => {
    // const response = await fetch(url);
    const response = await setTimeout(() => {console.log(1)}, 2000)
    return response;
  });

  // 按次序输出
  for (const textPromise of textPromises) {
    console.log(await textPromise);
  }
}
logInOrder(['a', 'b']);