Programming VIP

Due to browser differences, most js code contains a large number of if statements to guide the program to execute correctly. Examples are as follows: function createXHR() { if (typeof XMLHttpRequest != "undefined") { return new XMLHttpRequest(); //Returns an instance of XMLHttpRequest when the XMLHttpRequest type is not ...

set and map: these two data structures should be constructed through new. The parameters received by two data structures, one is a one-dimensional array and the other is a two-dimensional array. 1, Set data structure A Set is actually a data structure similar to an array. The difference is that there are no duplicate basic type values or ...

Recently, I met an interesting interview question. The question is very simple, but it involves a lot of small knowledge points. It's quite interesting. An ordinary for loop outputs i // Normally write a for loop and output i for (var i = 0; i < 5; i++) { console.log(i); } console.log(i); Suppose you are an interviewer, what will t ...

Ask yourself a few more questions each day about why, and you will always get unexpected results. A copyer for beginners Preface Today is the second day of National Day, come back home, or be bored, or write code. After all, the code is small and white, there is still a lot to learn, come on! Recently I was learning redux-saga as a middl ...

Enhanced writing of objects When defining the properties and methods of objects, it has a more convenient and simple way to write var name = "fzb"; var age = 21; var address = "address"; var info = { name: name, // A simple way to write attributes age, say: function () { console.log(this.name + " say~"); }, // A simple wa ...

Classes, Symbols, Objects, and Decorations class Use of classes // Declaration of class class Fruit { } // Equivalent to the declaration of a constructor function Fruit() { } Note: Class declarations differ from constructor declarations: Class declarations are not scoped ahead of time Properties and methods of classes Constructor ...

Inheritance plays an important role in various programming languages. Due to the "natural" flexibility of JavaScript, JS urgently needs a reusable and standardized solution in some scenarios. Classes and inheritance naturally appear in the public's vision. With the continuous in-depth study of JavaScript, we suddenly found that the c ...

webpack webpack is a front-end resource component tool, a static module bundler. Compile syntax that the browser does not recognize into syntax that the browser can recognize From the perspective of webpack, many resource files (js/json/css/img/less) in the front end will be processed as modules. It will conduct static analysis according to t ...

1, let const (1) let 1. Declared variables can only be valid within the current scope (the scope is {}) var is valid in the global scope (because the variables declared by var are on the whole object of Windows) example: Because the let will be invalid if it lists the current scope, each time the for loop goes, it is equivalent to ...

Inheritance is the basic concept of object-oriented language. Generally OO language supports two ways of inheritance: interface inheritance and implementation inheritance. Interface inheritance only inherits method signature, while implementation inheritance inherits the actual method. The function in ECMAScript is not signed, so interface i ...