es6 course

(x);}//Output://Hello// WorldAt line A, the symbol object is used as a key, and the key value is a method. This unique key allows the object to iterate and can be used for for-of looping.Purpose 2: Use constants to represent special meaningsIn ECMAScript 5, you might use strings to represent special meanings, such as colors. In ES6, you can use symbol because symbol is always unique:Constcolor_red = Symbol ('Red');ConstColor_orange = Symbol ('Orange'

Deconstruct and assignment of ES6 learning variables Deconstruct and assignment of Variables In ES6, variables can be extracted from arrays and objects in certain modes and assigned values. Deconstruct and assignment of Arrays var [a,b,c] = [1,2,3];a // 1;b // 2;c // 3; The code above indicates that values can be extracted from the array and assigned values based on the corresponding positions. Essentially,

ES6 modular import and export usage method summary, es6export Before ES6, The js module loading scheme has emerged. The most important is the CommonJS and AMD specifications. Commonjs is mainly used on servers for Synchronous loading, such as nodejs. AMD specifications are used in browsers, such as requirejs, for asynchronous loading. There are also CMD specifications for Synchronous loading solutions such

);*/ theConsole.log ("This dog is eating" +Food ); - }; - - functionCat () {} + varCATP =extend (cat,animal); -Catp.eat =function(food) { +Console.log ("This cat is eating" +Food ); A }; at varSnake =NewSnake (); -Snake.eat (' mouse ');//log: The animal is eating mice - varDog =NewDog (); -Dog.eat (' Bones ');//log: This dog is eating bones . - varCat =NewCat (); -Cat.eat (' fish ');//log: The cat is eating fishAbstract class:In the above code, the snake class does n

some elements, could it? Yes, the Fill () function provides parameters that specify the starting and ending positions of the fill.Or the above case, let's make a slight adjustment and then demonstrate:1 Let arr = [n/a]; 2 Arr.fill (4,1,3); 3 Results: [1,4,4]The 2nd and 3rd parameters in the above code mean that the element starting at position 1 is filled with the number 4, until position 3, so that the element of position 1 and position 2 is filled with the number 4, resulting in th

ES6 Essay--Extension of each data type (4)--extended extension operator for arrays and arrays of objectsThe form is three points, which is used to convert the ...数组 array to a comma-separated parameter sequence; equivalent to rest the inverse of a parameter;An extension operator can be followed by an expression, or an empty array without any effect;An extension operator can expand an array, instead of apply passing a parameter array to a function;// 扩

Expansion of arrays 1.1 extension Operators 1.1.1: ...The extension operator (spread) is a three-point ( ... ). It is like the inverse of the rest parameter, converting an array to a comma-delimited sequence of arguments. This operator is primarily used for function calls. function Add (x, y) { return x + y; } var numbers = [4,]; // theIn the above code, the add(...numbers) function is called, and it uses the extension operator. The

One, the copy of the arrayalert ([1,2,3]==[1,2,3]);Let CC = [0,1,2];let DD = CC;alert (DD==CC);//changing DD at this time will affect CCES5 can only use workarounds to copy arrays.= [1, 2];const a2 = a1.concat();a2[0] = 2;a1 // [1, 2]Using ES6 syntax prevents this behavior from appearingconst A1 = [12 ]; notation a const A2 = [..a1];//notation two const [.. .a2] = A1 alert ([' C ']==[' C ']);//falsealert ([' C ']===[' C ']);//falseExpansi

We used to define variables using Var, and ES6 gives us two ways to let and const (const is defined as constants). Today I will summarize let and Const. Simple, big god bird me. One, let define variable. We use a let-defined variable and a variable defined by VAR in es5 to differentiate. 1. Let-defined variable with block-level scopeWhat is a block-level scope, like {} curly braces, is a block-level scope. So let is declared within the block-level sco

characteristics of array deconstruction: let [x] = []; x = undefined var o = {},a =[]; [O.a, O.B, o.c,a[0]] = [1,2,3,4]; o:{a:1, B:2, C:3},a:[4] Let [x,... y] = ' abc ';//x= ' a '; y=[' B ', ' C '],rest operator var o = [1,2,3], A, B, C, P; p = [,, c] = [a,b] = o;//destructors continuous assignment trace (A + "" + B + "" +c); 1 2 3 trace (p = = O);/true var a1 = [1, [2, 3, 4,7,8], 5];//nested deconstruction +rest operator var [A, [B, C,... d], E] = A1; A=1,b=2,c=3,d=[4,7,8],e=5 Let's loo

IntroductionThe current react front-end frame is the hottest this year. React native, based on react, also developed rapidly. React has its unique component function and jsx new syntax to help the front-end design with better design and convenience, and react native is to expand the front-end boundaries.Speaking of react, you have to say that Webpack, with its excellent features such as asynchronous loading and detachable packaging, is on the way to replace grunt and gulp. And the future-oriente

This article describes how to parse the deconstruct assignment in the JavaScript ES6 version. The ES6 version has brought many simplified improvements to JS. If you need it, What Is deconstruct assignment? Deconstruct value assignment allows you to assign values of arrays and objects to a series of variables using syntax similar to arrays or object literal values. This syntax is concise and clearer than tr

ES5 's top-level object itself is also a problem, because it is not unified in various implementations. Inside the browser, the top-level object is window , but Node and Web Worker do not window . Inside the browser and Web Worker, self It also points to the top-level object, but Node does not self . Node, the top-level object is global , but no other environment is supported. The same piece of code in order to be able to take the top-level objects in various environments,

1. ES6 string Changes(1) The includes () method returns False if the specified text in the string is detected to return true(2) The StartsWith () method returns True if the text is detected at the beginning of the string, otherwise false(3) The EndsWith () method returns True if text is detected at the end of the string, otherwise falseAll of the above methods receive two parameters, one is the text to be detected, the second parameter is optional, th

ES6 (ECMAScript 2015) coding specifications and detailed attention points, combined with a large number of GF securities ES6 practice projects organized,Already open from GitHub, continuous update, welcome PR and issue.GitHub Address: https://github.com/gf-web/es6-coding-style/This specification is based on the JavaScript specification and is only intended for

(This article also published in my public number "dotnet daily Essence article", Welcome to the right QR code to pay attention to. )Preface: the title is preface.Since the release of Visual Studio code (originally 0.1), Microsoft has been continuously updating it. The day before yesterday just released 0.5, bringing the following new features: File-handling updates, such as: Opening a file from the command line and locating to a specific line Enhancements to Editor Options Significan

https://hacks.mozilla.org/2015/04/es6-in-depth-an-introduction/Counting to 6The previous editions of the ECMAScript standard were numbered 1, 2, 3, and 5.What is happened to Edition 4? An ECMAScript Edition 4 is once planned-and in fact a ton of work is done on it-but it is eventually scrapped as too am Bitious. (It had, for example, a sophisticated opt-in the static type system with generics and type inference.)ES4 was contentious. When the standards

function Extend (subclass, superclass) {2 function O () {3 This. constructor =Subclass;4 }5O.prototype =Superclass.prototype;6Subclass.prototype =Newo ();7 returnSubclass.prototype;8 }9 /*Ten subclass is a subclass, superclass is the parent class, the Extend function lets subclass inherit superclass's prototype method, and returns the subclass prototype; One This kind of inheritance is also used most, and the extends of ES6 is realiz

Point of this in es5 var factory = function(){ this.a = ‘a‘; this.b = ‘b‘; this.c = { a:‘a+‘, b:function(){return this.a} } };console.log(new factory().c.b()); // a+ Through es5 syntax call, the returned result is a +, and this points to the object called by the function, that is, who this points to when the function is called, which object calls this function? Who is this. Point of the arrow function this in es6 var factory =

1, ES6 provides a more approach to the traditional language, introduced the concept of Class (Class) as an object template. classyou can define a class by keyword.2.// Defining Classes class Point { constructor (x, y) { this. x = x; this. y = y; } ToString () { returnthis this. y + ') '; }}The above code defines a "class", and you can see that there is a constructor method in it, that is, the constructor method, and the this keyword rep