JS inheritance usage instance analysis and js inheritance instance analysis

JS inheritance usage instance analysis and js inheritance instance analysis

This article analyzes the usage of JS inheritance. Share it with you for your reference. The specific analysis is as follows:

Inheritance: Child classes do not affect the parent class. Child classes can inherit some features of the parent class (code reuse)

Property inheritance: call the constructor call of the parent class

Method inheritance: for in: Copy inheritance (jquery also uses copy inheritance extend)

1. Copy inheritance

Function Person (name) {this. name = name;} Person. prototype. showName = function () {alert (this. name);} function Worker (name, job) {Person. call (this, name); this. job = job;} extend (Worker. prototype, Person. prototype); // If Worker is used. prototype = Person. prototype causes reference of the same problem function extend (obj1, obj2) {for (var I in obj2) {obj1 [I] = obj2 [I]} var coder = new Worker ('magicfly ', 'frontend'); coder. showName ();

2. class inheritance

Function Person (name) {this. name = name;} Person. prototype. showName = function () {alert (this. name);} function Worker (name, job) {Person. call (this, name); this. job = job;} // Worker. prototype = new Person (); // This inheritance will inherit the unnecessary attribute function F () {}; F. prototype = Person. prototype; Worker. prototype = new F (); // It is solved by creating a temporary constructor, also known as the proxy function var coder = new Worker ('magicfly ', 'start'); coder. showName ();

3. Prototype inheritance

Var a = {name: 'xiaoming '}; var B = cloneObj (a); B. name = 'xiaoqiang'; // alert (B. name); alert (. name); function cloneObj (obj) {var F = function () {}; F. prototype = obj; return new F ();}

Applicability

Copy inheritance
Class inheritance: new Constructor
Prototype inheritance: objects without new

I hope this article will help you design javascript programs.