js promise

, the then method can accept two parameters, the first corresponding to the resolve callback, and the second to the reject callback. So we were able to get the data that they had handed over. Run this code multiple times, and you'll randomly get the following two kinds of results: Or Use of CatchWe know that the Promise object has a catch method in addition to the then method, what does it do? In fact, it is the same as the second parameter of then, w

Promise object in Angular ($ q Introduction) This article mainly introduces the Promise object in Angular ($ q Introduction). This article describes the Promise mode, the basic usage of Q Promise, and the $ q in AngularJs. defferd and other content. For more information, see When using JQuery, we know that

: ' // add error events at the same time var p = new Promise (function (resolve, reject) {resolve ( "OK" ); throw new Error (' Error0 ' ); SetTimeout ( function () {throw Span style= "color: #0000ff;" >new Error (' Error1 ')}, 0 function (value) {Console.log ( Value)}). catch (Funcrion (err) {Console.log (Err)}) ;Process.on (function (err, p) {console.error (' catch exception: ', Err.stack)});First put the problem here, if one ca

This article mainly introduces the Promise object in Angular ($ q introduction). This article describes the Promise mode, the basic usage of QPromise, and $ q in AngularJs. defferd and other content. if you need it, you can see that when using JQuery, you will know that promise is a Js asynchronous programming mode, bu

This article mainly introduces the Promise object in Angular ($ q Introduction). This article describes the Promise mode, the basic usage of QPromise, and $ q in AngularJs. defferd and other content. If you need it, you can see that when using JQuery, you will know that promise is a Js asynchronous programming mode, bu

: {then:function(){ if(Pending) {Pending.push (callback); }Else{callback (value); } } } }; returnself.promise;};Implement Promise CascadeThe next step will be a very important one. To the front of the Q3, the implementation of the promise are not cascading. But the promise you are familiar with sh

(1) Why use this design pattern of promise, what are the benefits of this design pattern?The traditional way to solve a JavaScript asynchronous event is to call a callback function, invoke a method, then give it a function reference, and execute the function reference when the method ends.Artifact from Javascript--promisepromise in JS callback function The real problem is that he deprives us of the

Promise in JS callback function The real problem is that he deprives us of the ability to use return and throw these keywords. And Promise a good solution to all this. In June 2015, the official version of ECMAScript 6 was finally released.ECMAScript is an international standard for JavaScript, and JavaScript is the implementation of ECMAScript. The

The promise in the angular When you use jquery, you know promise is a pattern of JS asynchronous Programming mode, but it's not quite clear what difference he has with jquery's deferred object. With the company project, to the background with the data, so decided to fix it. Promise

What is promise Promise is a more elegant pattern of writing asynchronous code, allowing asynchronous operation code to be written and read like synchronous code, such as the following example of an asynchronous request: $.get ("/js/script,js", function () { //callback to do }) Can be rewritten as

When you use jquery, you know promise is a pattern of JS asynchronous Programming mode, but it's not quite clear what difference he has with jquery's deferred object. With the company project, to the background with the data, so decided to fix it. Promise Promise is a mode in which asynchronous events are manipulated

What's Angularjs? Angularjs was born in 2009, by Misko Hevery and other people to create, after the acquisition of Google. is an excellent front-end JS framework, has been used in a variety of Google products. Angularjs has many characteristics, the most core is: MVVM, modular, automated two-way data binding, semantic tagging, dependency injection, and so on Promise