本文介绍了从 setTimeout 获取返回值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我只是想从 setTimeout 中获取返回值,但我得到的是函数的完整文本格式?
I just want to get the return value from setTimeout but what I get is a whole text format of the function?
function x () { setTimeout(y = function () { return 'done'; }, 1000); return y; } console.log(x()); 推荐答案你需要为此使用 Promise.它们在 ES6 中可用,但可以使用 polyfill很容易:
You need to use Promises for this. They are available in ES6 but can be polyfilled quite easily:
function x() { var promise = new Promise(function(resolve, reject) { window.setTimeout(function() { resolve('done!'); }); }); return promise; } x().then(function(done) { console.log(done); // --> 'done!' });在 ES2017 中使用 async/await 如果在 async 函数中会变得更好:
With async/await in ES2017 it becomes nicer if inside an async function:
async function() { const result = await x(); console.log(result); // --> 'done!'; }更多推荐
从 setTimeout 获取返回值
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