es6 course

Promise:Before ES6, if we need to do asynchronous processing in JS, most are solved by using callback functions, and if simple asynchronous processing, the callback function looks elegant, the force is still a bit high, but if there are many asynchronous operations, the callback nesting is very deep, the code will look particularly awkward , maintenance costs will also become higher this time ES6 bring prom

‘], function (jQuery, _) { return factory(jQuery, _); }); } else if (typeof exports === ‘object‘) { // Node.js module.exports = factory(require(‘jquery‘), require(‘underscore‘)); } else { // Browser globals root.Backbone = factory(root.jQuery, root._); }}(this, function (jQuery, _) { var Backbone = {}; // Backbone code that depends on jQuery and _ return Backbone;}));You can see why this is not popular, it is too scary, no one will write, look at it, I just want to curse.

ES6 Iterator (Iterator) and for. of loop usage method learning (Summary), es6for. 1. What is an iterator? The generator concept is available in Java, Python, and other languages, and ES6 is also added to JavaScript. Iterator allows us to use the next method of the Iterator object instead of initializing the set and the index variables. Instead, it returns the value of the next item of the Set, which is more

) { if (button) { button.prop("disabled", true); } var deferred = $.Deferred(); $.ajax(url, { type: "post", dataType: "json", data: data }).done(function(json) [ if (json.code !== 0) { showError(json.message || "操作发生错误"); deferred.reject(); } else { deferred.resolve(json); } }).fail(function() { showError("服务器错误，请稍后再试"); deferred.reject(); }).always(function() { if (button)

is "bound" to the area and is no longer affected by the external. var tmp = 123; if (true) { TMP = ' abc ';//referenceerror:tmp is not defined let tmp; } In the above code, the global variable TMP exists, but the block-level scope let also declares a local variable tmp, which causes the latter to bind the block-level scope, so the TMP assignment will be an error before let declares the variable. ES6 explicitly states that if a let and a cons

1. PrefaceBecause the ES6 syntax is supported on various browsers, some browsers have a high degree of support for ES6 syntax, and some browsers support low, so in order to be compatible with most browsers, we need to use the Babel compiler to compile the ES6 syntax in the code into ES5 syntax when using ES6 syntax. Be

ECMAScript6 (ES6) is the latest JavaScript standard. Because the current version of ES6 was released in 2015, it is also called ECMAScript2015. Small programs support most of the new features of ES6. C... ECMAScript 6 (ES6) is the latest standard for JavaScript. Because the current version of

Here's a brief look at the implications of these new language features for the development of React applications, which make React development simpler and more interesting.ClassSo far, the best embodiment of our use of es6+ to write React components is that we chose to use the class definition syntax. Instead of using the React.createclass method to define a component, we can define a bonafide ES6 class to

Previous wordsThe array is a basic JS object, and as time progresses, the rest of JS is evolving, and until the ES5 standard introduces some new methods to simplify the use of the array object. The ES6 standard continues to improve the array, adding many new features. This article describes in detail the ES6 array extensionCreate an arrayBefore ES6, there are two

注：ES6的一些新属性会显示语法错误，不过不会影响效果，在Languages里面也可以调；Let: used to define variables特点：只能在代码块里面使用,let拥有块级作用域;并且let不允许重复声明;比如: var a = 12; var a = 5; alert(a);//5; let a = 12; let a = 5; alert(a);//报错;Identifier ‘a‘ has already been declared代码块:{}包起来的代码,形成了一个作用域,比如if,for,while,json除外;块级作用域;var 只有函数作用域;用处: 自执行函数: for(let i = 0; i Const: Typically used to define constants常量:不允许修改;有些时候定的变量不希望被改变,这个不希望被改变的值就是常量;比如:let a = 5; a = 12; alert(a);//12;其实

ES6 Let (understanding closures) and Const commandsRecently, the process of doing the project, the use of ES6, because few contact before, so the use is not familiar. Therefore purchased the Nanyi Teacher's ES6 standard introduction, here Thanks Nanyi Teacher's book.We know that ECMAScript 6, ES6, is the fifth version

How to use Set, WeakSet, es6setweakset in ES6 ES6 provides two new data structures: Set and WeakSet. Set is similar to an array, but the values of member variables are unique and there are no repeated values. WeakSet is also a set of non-repeated values, but can only be used to store objects. 1. Set usage (1) Set itself provides a constructor to generate a Set data structure. var s = new Set();[2,2,2,5,8,16

ES6 is extended for numeric types (number):1. A new notation for binary and octalES6 provides a new notation for binary and octal values, expressed in 0b (or 0B) and 0o (or 0o) respectively. For example:0b111110111 = = = 503 // true= = = 503 //trueSince ES5, in strict mode, octal is no longer allowed to use the prefix zero, so it is further clarified in the ES6 and is represented by 0o.If you want to con

Application code parsing of es6 in react and es6react code parsing Whether React or React-native, facebook officially recommends ES6 syntax. If ES6 is not used in projects, some problems may occur during the conversion, if there is no time for the system to learn ES6, it is enough to pay attention to some common writin

call an array after you convert it into a real array, but it's not easy to understand and too "winding", ES6 gives us a simpler and more straightforward way of using a form that is simple to use: var inputobjs=document.getelementsbytagname (' input '); Console.info (INPUTOBJS); []length:0__proto__: Htmlcollection console.info (Array.from (INPUTOBJS));//[]length:0__proto__: Array[0] The result is the same but semantically more appropriate

Es6 added three points of functionality, three points have expanded (spread) and rest (rest) of these 2 functions, first look at the unfolding Let's take a look at an example and create a function function fn (a,b,c) { console.log (a,b,c); } FN (1,2,3);This print is 1,2,3, and then if you build an array, the arguments pass an array. function fn (a,b,c) { console.log (a,b,c); } Let arr=[2,3,4]; FN (arr);This printout is [2, 3, 4] undefined undefi

Database questions: Student table, Course Selection table, course schedule, course schedule There are three basic tables in the teaching database: Student table S (S #, SNAME, AGE, SEX). Its Attributes indicate the student's student ID, name, AGE, and gender. The course selection table SC (S #, C #, GRADE ), the attrib

A word summary: using Webstorm's own file Watcher function +babel to achieve automatic conversion ECMAScript 6 code for ES5 code1.Create a new empty Project, and then create a new main.js in the SRC directory;This step is not necessary, just get started. It will be much less disruptive to start your own configuration from an empty project.2.Enter settings to change JavaScript language version to ECMAScript 6;3.And then. Write a section of ES6 code'Use

ES6 introduced a lot of new syntax features, but want to do in the existing browser environment, need to ES6 code to ES5 code, there are many transcoding babel,traceur, etc., after reference, use Traceur and gulp to build ES6 environment, start my ES6 .Start installationFirst make sure the Nodejs is installed on your c

Recently studying ES6 in the ES6 series with Nanyi, some errors were found in the Let and Const commands chapter, which listsFirst, let does not exist the variable promotion assumes that there is no variable promotion, then in the Ruan Feng article this code code is correctfunction do_something () { console.log (foo);//Referenceerror let foo = 2;}The program will report referenceerror errors, while the ac