es6 course

advance.B.foo ()}});CMD is another JS modular scheme, and it is similar to AMD, the difference is that AMD respected the reliance on pre-and early-execution, CMD respected near-dependency, deferred execution. This specification is actually produced in the process of sea.js promotion./ AMD notation /Define (["A", "B", "C", "D", "E", "F"], function (A, B, C, D, E, f) {is equal to the first declaration and initialization of all modules to be usedA.dosomething ();if (false) {Even though it didn't w

Can a function be declared in a block-scoped scope? This is a rather confusing question.ES5 states that functions can only be declared in the top-level scope and function scope, not at the block-level scope.1 //situation one2 if(true) {3 functionf () {}4 }5 6 //Scenario Two7 Try {8 functionf () {}9}Catch(e) {Ten // ... One}The above two function declarations, according to the provisions of ES5 are illegal.However, the browser does not adhere to this rule, in order to be compatible with the

Here is the recursive/trailing recursive implementation of the reverse sequence (array/string) made with JavaScript. In addition, the early adopters used a ES6 destructuring assignment + spread operator to make a more functional version (only supported arrays).Correctness can pass the test (see the demo on my Github and write a small test frame), but efficiency is mark-especially with the ES6 feature versio

http://es6.ruanyifeng.com/#READMEHttps://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference(1) Arrow operatorIf you have C # or Java, you must know the lambda expression, the new arrow operator in ES6. It simplifies the writing of functions. The left side of the operator is the input parameter, and the right side is the action to be taken and the value returned inputs=>outputs.We know that the callba

, Elem = C The for-of loop of the ES6 supports ES6 iterations (through Iterables and iterators) and deconstruction. If you use the new method of the array enteries () to combine the deconstruction, you can achieve the same effect as the above ForEach: Const arr = ["A", "B", "C"]; for (const [index, elem] of arr. Entries()) { console. Log('index = ${index}, ele

React native is the direct use of ES6 to write code, many new syntax can improve our productivityDeconstruction Assignmentvar { StyleSheet, Text, View} = React;This code is the new deconstruction (destructuring) assignment statement in ES6. Allows you to get multiple properties of an object and assign them to multiple variables using a single statement.The above code is equivalent to:var StyleSheet = Rea

Why do ES6 have compatibility issues? Because the majority of users use the browser version at the time of release may be earlier than the ES6 and release, and today, if we use the new features of ES6 in programming, if the browser does not have a newer version, or the new version of the ES6 features are not compatible

1, the tag is opened defer or the async property , the script will be loaded asynchronously. When the rendering engine encounters this line of command, it begins to download the external script, but does not wait for it to be downloaded and executed, but executes the following command directly.deferasyncthe difference is that the former will not be executed until the entire page is rendered normally, and once downloaded, the rendering engine interrupts rendering, executes the script, and then

In view of the recent development of projects with the VUEJS framework, many of them involve the ES6 grammar which is not well understood in order to read the book carefully.Address: http://es6.ruanyifeng.com/#README　　Chapter One: Let, const commands, and block-level scopesES6 adds a declarative keyword for both the Let and the const variables, which greatly reinforces the JS variable's reasonableness and f

1 overview The traditional method of JavaScript language is to define and generate new objects by using constructors. Here is an example. function point (x, y) { this.x = x; This.y = y; } Point.prototype.toString = function () {return ' (' + this.x + ', ' + this.y + ') '; var p = new Point (1, 2);The above is very different from the traditional object-oriented language, such as C + + and Java, and it is easy to confuse the new programmer who is learning the language.

Proxy and reflect implementation overload) In terms of syntax, JavaScript does not support overloading. The reason is very simple. In JS, a function can input any type or number of parameters, which can be obtained by using this. arguments in the function. In this way, different functions cannot be implemented in different parameter lists of functions with the same name. Of course, in actual use, you can manually check the number and type of input rea

In the spirit of sharing the Internet, I will share my understanding of promise to you.The Promise method of JavaScript ES6 is mainly applied to the result of handling the return of an asynchronous function, noting that he is not converting an asynchronous function to a synchronous function, but when the asynchronous function has the result when the corresponding method is called to process.Promise has the following methodsThen ()-it requires a maximu

What is deconstruction? Deconstruction is diametrically opposed to structured data. For example, instead of constructing a new object or array, it splits an existing object or array one by one to extract the data you need. ES6 uses a new pattern to match the values you want to extract, and the solution assignment is to use this pattern. The pattern maps out the data structure you are deconstructing, and only those data that match the pattern are ext

Let's see how the es6 of the new characteristic variable is convenient to print out the variable First, let's take a look at what Es5 did before, stating that an object Let obj={ firstName: ' Mike ', lastName: ' Hurley ' } let f=obj.firstname, l=obj.lastname; Console.log (' ${f} ${l} ');We use the F and L two variables to receive the two attributes of the Obj object, this is the writing of ES5, Es6

This article describes the babel6.x installation process ~ First of all, you can use the Babel online conversion https://babeljs.io/repl/ Then go to the topic: Install Babel (command line environment, for babel6.x version) 1, first install BABEL-CLI (used in the terminal to use Babel) NPM install-g BABEL-CLI 2, then install the babel-preset-es2015 plugin NPM Install--save babel-preset-es2015 　　Note: The BABEL5 version defaults to include a variety of conversion plug-ins, however babel6.x

One, the expansion of the array, ES6 in the array to expand some of the API to achieve more functionality1.array.from: You can convert a class array and a data structure that can be traversed to a real array, as shown belowvar a = {' 0 ': 1, ' 1 ': 1,length:2};var arr = Array.from (a); Console.log (arr) Array [1, 1]---------------ES5 implementation-----------var arr = [].slice.call (a); Console.log (arr) Array [1, 1]function Fun () {var arr = array.fr

ES6 new features (Class) and inheritance (Extends) Related Concepts and Usage Analysis, es6extends This article describes the concepts and usage of new features such as ES6 and Extends. We will share this with you for your reference. The details are as follows: I. Class) 1. Basic syntax The traditional method of JavaScript is to define and generate new objects through constructors. The following is an examp

The main difference between the Commonjs module and the ES6 module is that thecommonjs module is a copy, the ES6 module is a reference , but understanding these, first understand the problem of object replication, in retrospect to understand the difference between the two modules.One, the basic data type module./a1.jsES6 Moduleexportvar=1;setTimeout=>=2,500);./a2.jsCOMMOJS Modulevar=2;module.exports= a2;set

quickly. But after ECMASCript 3 came out of 1999, there were no changes made to the official for a standard. Instead various browser vendors made their own custom extensions to the language, and Web developers were left to try and Support multiple APIs. Even after ECMAScript 5 is published in 2009, it took several years for wide browser support of the new spec, and most de Velopers continued to write code in ECMAScript 3 style, without necessarily being the aware. Around things started to cha

As a rest parameter, the three-point operator can play an important role in functions, deconstruction assignments, and so on. ' As the name ', rest means the rest, it pushes the remaining number of arguments into the array, so it inherits the method of the array. The rest parameter can only appear in the last one, or it will be an error, of course, to expand the identity of the operation is a matter of case.