JS中的继承总结

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1. 原型链继承

Child.prototype = new Parent();

 1 function Parent (name, age) { 2     this.name = name; 3     this.age = age; 4 } 5 Parent.prototype.say = function(){ 6     console.log('hello, my name is ' + this.name); 7 }; 8 function Child() { 9 }10 Child.prototype = new Parent('pursue');11 var child1 = new Child();12 child1.say(); //hello, my name is pursue13 var child2 = new Child();14 console.log(child1.say === child2.say);//true15 console.log(child1.name === child2.name);//true

2. call(thisObj, param1, param2,...)

 1 function Parent(username){ 2     this.username = username; 3     this.hello = function(){ 4       alert(this.username); 5     } 6   } 7   function Child(username,password){ 8     Parent.call(this,username); 9     this.password = password;10     this.world = function(){11       alert(this.password);12     }13   }14   var parent = new Parent("zhangsan");15   var child = new Child("lisi","123456");16   parent.hello();17   child.hello();18   child.world();

3. apply(thisObj, [param1,param2,...])

 1 function Parent(username){ 2     this.username = username; 3     this.hello = function(){ 4       alert(this.username); 5     } 6   } 7   function Child(username,password){ 8     Parent.apply(this,new Array(username)); 9     this.password = password;10     this.world = function(){11       alert(this.password);12     }13   }14   var parent = new Parent("zhangsan");15   var child = new Child("lisi","123456");16   parent.hello();17   child.hello();18   child.world();

4. 组合继承(call+原型链 / apply+原型链)

 1 function Parent(hello){ 2     this.hello = hello; 3   } 4   Parent.prototype.sayHello = function(){ 5     alert(this.hello); 6   } 7   function Child(hello,world){ 8     Parent.call(this,hello);//利用 call 方法 将父类的属性继承过来 9     //Parent.apply(this,new Array(hello));//利用 apply 方法 将父类的属性继承过来10     this.world = world;//新增一些属性11   }12   Child.prototype = new Parent();//将父类的方法继承过来13   Child.prototype.sayWorld = function(){//新增一些方法14     alert(this.world);15   }16   var c = new Child("zhangsan","lisi");17   c.sayHello();18   c.sayWorld();

5.寄生组合继承，与4相似，只是将原型链换做了Object.create(Parent.prototype)

 1 function Parent(hello){ 2     this.hello = hello; 3   } 4   Parent.prototype.sayHello = function(){ 5     alert(this.hello); 6   } 7   function Child(hello,world){ 8     Parent.call(this,hello);//利用 call 方法 将父类的属性继承过来 9     //Parent.apply(this,new Array(hello));//利用 apply 方法 将父类的属性继承过来10     this.world = world;//新增一些属性11   }12   Child.prototype = Object.create(Parent.prototype);//将父类的方法继承过来13   Child.prototype.sayWorld = function(){//新增一些方法14     alert(this.world);15   }16   var c = new Child("zhangsan","lisi");17   c.sayHello();18   c.sayWorld();

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