JavaScript async/await 入门指南

掌握 JavaScript 的 async/await、Promise 与 fetch。用清晰可测的模式处理 API 调用、错误与并行请求。

async/await in JavaScript

JavaScript 单线程但非阻塞。async/await 让你写出读起来像同步的异步代码 — 对 fetch、数据库与定时器必不可少。

Why JavaScript async await Matters

Every API call, database query, and file read in modern JavaScript is asynchronous — async/await is how you manage that complexity.

await only works inside async functions; wrap await in try/catch because rejected Promises become catchable errors.

JavaScript async await — Key Ideas You Must Know

Promise 表示未来的值
async 函数始终返回 Promise
await 暂停直到 Promise 完成
try/catch 处理异步错误
Promise.all 并行请求

JavaScript async await Code Example

JAVASCRIPT

async function loadUser(id) {
  try {
    const res = await fetch(`/api/users/${id}`);
    if (!res.ok) throw new Error('Failed');
    return await res.json();
  } catch (err) {
    console.error(err);
  }
}

Practice JavaScript async await with Free Lessons

完成 Sturdee 的 async/await 课程，用 fetch 做天气小应用。

Tip: Free interactive lesson: /tutorials/javascript/javascript_async — practice JavaScript async await with runnable code on Sturdee.

JavaScript async/await — FAQ

Frequently Asked Questions

async/await 和 .then() 哪个好？+

底层都是 Promise。顺序逻辑用 async/await 更清晰。

JavaScript async/await — 初学者完整指南