Inheritance in JavaScript

First, the prototype chain (default)

function person () {};

function Student () {};

Student.prototype = new Person ();

Student.prototype.constructor = Student;

Cons: 1, how to do the argument? 2. The instance property of new person is the prototype attribute of student.

Second, borrowing the constructor function

function person (name) {this.name = name;}

function Student (name, Klass) {Person.call (this, name); This.klass = Klass;}

Advantages: The communication has been done. Disadvantages: How inheritance is inherited?

Third, combinatorial inheritance (prototype chain + borrowing constructors)

1 functionPerson (name) {2      This. Name =name;3 }4 5 functionStudent (name, Klass) {6Person.call ( This, name);7      This. Klass =Klass;8 }9 TenStudent.prototype =NewPerson (); OneStudent.prototype.constructor = Student;

There are drawbacks: 1. The instance property of new person is a prototype attribute of Student 2 the person constructor was called two times, inefficient

Iv. Temporary constructors

1 functionPerson (name) {2      This. Name =name;3 }4 5 functionStudent (name, Klass) {6Person.call ( This, name);7      This. Klass =Klass;8 }9 Ten(function(){ One     varF =function(){}; AF.prototype =Person.prototype; -Student.prototype =NewF (); -Student.prototype.constructor =Student; the})();

It looks good ~ ~

But why does JavaScript have to be a type of inheritance pinch

Here's the point,

Prototype inheritance

Student.prototype = Object.create (Person.prototype);

Student.prototype.constructor = Student;

Prototype chain, chain up: New Student ()-----> Student.prototype----->person.prototype-----> Object.prototype

Put your heart, my heart, string a string, a string of lucky grass, string a concentric circle ~ ~

Object.create Polyfill

if (typeof object.create!== ' function ') {    function(o) {        var  function() {};         = o;         return New F ();    }}

Additional, inheritance is implemented by copying properties

1 functionExtenddeep (parent, child) {2     vari;3Child = Child | | {};4      for(Iinchparent) {5         if(Parent.hasownproperty (i)) {6             if(typeofParent[i] = = = ' object '){7Child[i] = (Object.prototype.toString.call (parent[i]) = = = ' [Object Array] ')? [] : {};8 Extenddeep (Parent[i], child[i]);9}Else{TenChild[i] =Parent[i]; One             } A         } -     } -     returnChild ; the}

Inheritance in JavaScript