js promise

In this article, we will explore the concepts of Deferred and Promise in JavaScript. They are a very important feature in the JavaScript Toolkit (such as Dojo and MochiKit, it has also made its debut in the popular JavaScript library jQuery (which is already in version 1.5 ). Deferred provides an abstract non-blocking solution (such as Ajax Request Response). It creates a "promise" object to return a respon

A few days ago in the interview, encountered such a question: Name the execution result of the following code: settimeout (function () { console.log (1) }, 0); New Promise (function executor (resolve) { resolve (); }). Then (function () { console.log (2); }); 2,1 (function test () { settimeout (function () {Console.log (4)}, 0); New Promise (function executor (resolve) { console.log (

implementing the next operation. Starting with ES6, promise objects can solve the above problems. What is a Promise object A Promise object can be understood as an action to be performed once, and a promise object can be used after a chain call To organize your code to make it more intuitive. Resolve and Reject First

In this article, we explore the concepts of Deferred and Promise in JavaScript, a very important feature of JavaScript toolkits (such as Dojo and MochiKit), and have recently been unveiled in the popular JavaScript library for the first time. JQuery (already a version of the 1.5 thing). Deferred provides an abstract non-blocking solution, such as a response to an AJAX request, that creates a "promise" objec

In this article, we will explore the concepts of Deferred and Promise in JavaScript. They are a very important feature in the JavaScript Toolkit (such as Dojo and MochiKit, it has also made its debut in the popular JavaScript library jQuery (which is already in version 1.5 ). Deferred provides an abstract non-blocking solution (such as Ajax Request Response). It creates a "promise" object to return a respon

Basic knowledge: Promise (finishing)(from the Cattle network) The following statement about promise, the wrong is (D)A. Both resolve and reject directly generate a promise object that enters the corresponding state, and its parameters are passed in the corresponding state when passing parameters, which can be obtained in the parameters of the completion callbackB

Many languages, in order to process asynchronous patterns more in the usual order, contain an interesting scenario library, which is called promises,deferreds, or futures. The promises of JavaScript can facilitate separation of concerns to replace tightly coupled interfaces. This article is about the JavaScript promises based on the PROMISES/A standard. [Http://wiki.commonjs.org/wiki/Promises/A] Use cases for promise: Executing rules Multip

What is promise? Is it an object? Array? Function? We can print it out directly, console. dir (promise) It can be seen that promise is a constructor, which has the "all", "reject", and "resolve" methods on its own, and the then and catch methods on its prototype. In this case, the then and catch methods must be applied to the objects created by using

The deferred object of the Promise objectPortal Instance Environment setup----------------------------------------------1. What is scaffolding: Others set up a good environment to download and useAjaxParallel/serialPromise.all-----------------------------------------------Promise.allRequest two at the same time and then return as if there is one error the other one also goes wrong-----------------------------------------------Const Getjson = function

Javascript Promise learning notes, javascriptpromise 1. Definition: Promise is a component that abstracts asynchronous processing objects and performs various operations on them. It uses asynchronous processing objects and asynchronous processing rulesUnified Interface. 2. API defined in ES6 Promises standard: A)Constructor: new is used for instantiation,Var promise