ThePromise.allmethod takes an iterable of promises as a parameter and returns a single promise that resolves to an array of the results of the given promises. This returned promise resolves when all promises have resolved. It rejects immediately upon any of the input promises rejecting with error...
At any moment in time, promises can be in one of three states: unfulfilled, resolved or rejected.To give an idea how the concept works, let’s start out with the CommonJS Promise/A proposal which has several derivatives in popular libraries. The then method on the promise object adds ...
# Working with Promises Alternately, instead of using the done() callback, you may return a Promise. This is useful if the APIs you are testing return promises instead of taking callbacks: beforeEach(function() { return db.clear().then(function() { return db.save([tobi, loki, jane]);...
然后,你可以看到.then()方法连接到了fetch()末尾 - 这个方法是Promises的一部分,是一个用于执行异步操作的现代 JavaScript 特性。fetch()返回一个 promise,它将解析从服务器发回的响应。我们使用then()来运行一些后续代码,这是我们在其内部定义的函数。这相当于 XHR 版本中的onload事件处理程序。
Working with Promises takes some getting used to. In particular, you need to understand where to use await, to stop and wait for a result, and where instead to use a Promise's then() method, to immediately carry on and process the result later. If you accidentally omit the await keyword...
All of the other methods on a promise have static analogs with the same name.The following are equivalent:return Q.all([a, b]);return Q.fcall(function () { return [a, b]; }) .all();When working with promises provided by other libraries, you should convert it to a Q promise. ...
Various utilities and convenience functions for working with promises.Method Overview NameReturn TypeSummaryObject createAbortError() Error Creates a special error object which is used to signal aborted requests in promise chains. promiseUtils debounce() Function A utility for ensuring an input ...
All of the other methods on a promise have static analogs with the same name.The following are equivalent:return Q.all([a, b]);return Q.fcall(function () { return [a, b]; }) .all();When working with promises provided by other libraries, you should convert it to a Q promise. ...
You must use a Promise method to handle promises. Promise How To Here is how to use a Promise: myPromise.then( function(value) {/* code if successful */}, function(error) {/* code if some error */} ); Promise.then() takes two arguments, a callback for success and another for ...