async／await让你的代码更加优雅

一. 回调地狱：回调函数里面嵌套着回调函数嵌套着回调函数”，这就是被传说中的“回调地狱callbackHell () { const api = new Api() let user, friends api.getUser().then(function (returnedUser) { user = returnedUser api.getFriends(user.id).then(function (returnedFriends) { friends = returnedFriends api.getPhoto(user.id).then(function (photo) { console.log('callbackHell', {user, friends, photo}) }) }) })}二. 如何优雅解决回掉地狱1. promise chain promiseChain () { const api = new Api() let user, friends api.getUser() .then((returnedUser) => { user = returnedUser return api.getFriends(user.id) }) .then((returnedFriends) => { friends = returnedFriends return api.getPhoto(user.id) }) .then((photo) => { console.log('promiseChain', { user, friends, photo }) }).catch((err) => {　　　 console.error(err) 　　})}2. await/async async asyncAwaitIsYourNewBestFriend () {　　try { 　　 const api = new Api() 　　 const user = await api.getUser() 　　 const friends = await api.getFriends(user.id) 　　 const photo = await api.getPhoto(user.id) 　　 console.log('asyncAwaitIsYourNewBestFriend', { user, friends, photo })　　} catch (err) { console.error(err) }}  

 

转载于:https://www.cnblogs.com/fancyLee/p/9268716.html

相关资源：async/await优雅的错误处理方法总结