JS ES7 async & await

最新推荐文章于 2022-10-19 18:58:51 发布

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本文深入探讨了async/await语法在JavaScript中的应用，并通过实际案例展示了如何使用fetch API进行HTTP请求，实现了异步操作的优雅处理。

async & await

async function myFunc(){  //返回一个promise
  // return `Hello`;

  const promise = new Promise((resolve,reject)=>{
    setTimeout(()=> resolve(`Hello`),1000);
  });

  const error = true;

  if(!error){
    const res= await promise; //wait until promise is resolved
    return res;
  }else{
    await Promise.reject(new Error(`Something went wrong`));
  }
}

// console.log(myFunc());
myFunc()
.then(res=>console.log(res))
.catch(err=> console.log(err));

用async & await + fetch get http

async function getUsers(){
  //await response of the fetch call
  const response = await fetch('https://jsonplaceholder.typicode.com/users');

  //only proceed once its resolved
  const data = await response.json();
  //only proceed second promise is resolved
  return data;
}

getUsers().then(usrs => console.log(usrs));