理解js对象继承的N种模式

本文分享了js对象继承的N种模式，供大家参考。

一、原型链继承

Person.prototype = {
constructor: Person,name: "Oliver"
};

function People(){};

People.prototype = new Person();
People.prototype.constructor = People;
People.prototype.sayName = function(){
return this.name;
};

var ins = new People();

console.log(ins.sayName());

二、借用构造函数（伪造对象，经典继承）

1、无参数

var instance1 = new SubType();
var instance2 = new SubType();

instance1.color.pop();
console.log(instance1.color); //["red","yellow"]
console.log(instance2.color); //["red","white"]

2、有参数

var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);

instance2.number.pop();

console.log(instance1.name + instance1.age + instance1.number); //Oliver1821,1
console.log(instance2.name + instance2.age + instance2.number); //Troy2421,14

三、组合继承（伪经典继承）

1、无参数

function SubType(){
SuperType.call(this);
this.number = 321;
}
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
SubType.prototype.sayNumber = function(){
return this.number;
};

var instance1 = new SubType();
var instance2 = new SubType();

instance2.color.pop();
console.log(instance1.color + instance1.number); //red,yellow,white321
console.log(instance2.color + instance2.number); //red,yellow321

2、有参数

function SubType(name,name);
this.age = age;
}
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
SubType.prototype.sayAge = function(){
return this.age;
};

var instance1 = new SubType("Oliver",24);

instance2.number.pop();
console.log(instance1.sayName() + instance1.sayAge() + instance1.number); //Oliver1832,1
console.log(instance2.sayName() + instance2.sayAge() + instance2.number); //Troy2432,11

三、寄生组合式继承（引用类型最理想的范式）

function SuperType(name){
this.name = name;
this.number = [321,321,43];
}
SuperType.prototype.sayName = function(){
return this.name;
};

function SubType(name,name);
this.age = age;
}
inheritPrototype(SubType,SuperType);
SubType.prototype.sayAge = function(){
return this.age;
};

var instance1 = new SubType("Oliver",24);
instance2.number.pop();

console.log(instance1.sayName() + instance1.sayAge() + instance1.number); //Oliver18321,43
console.log(instance2.sayName() + instance2.sayAge() + instance2.number); //Troy24321,321

或者可以把inheritPrototype 函数写成下面这样：

四、原型式继承（用于共享引用类型的值，与寄生式类似）

1、传统版（先定义object() 函数，再继承）

var SuperType = {
name: "Oliver",number: [321,4532,1]
};

var SubType1 = object(SuperType);
var SubType2 = object(SuperType);

SubType1.name = "Troy";
SubType1.number.pop();

SubType2.name = "Alice";
SubType2.number.pop();

console.log(SubType1.name + SubType2.name + SubType1.number + SubType2.number + SuperType.name + SuperType.number); //TroyAlice321,321321,321Oliver321,321

ECMAScript 5 版（直接用Object.create()，再继承）

var SubType1 = Object.create(SuperType); //省略了定义object()函数
var SubType2 = Object.create(SuperType);

SubType1.name = "Troy";
SubType1.number.pop();

SubType2.name = "Alice";
SubType2.number.pop();

console.log(SubType1.name + SubType2.name + SubType1.number + SubType2.number + SuperType.name + SuperType.number); //TroyAlice321,321

ECMAScript 5 简写版（定义Object.create()的第二个参数，再继承）

var SubType1 = Object.create(SuperType,{
name: {
value : "Troy"
}
});
var SubType2 = Object.create(SuperType,{
name: {
value : "Alice"
}
});

SubType1.number.pop();
SubType2.number.pop();

console.log(SubType1.name + SubType2.name + SubType1.number + SubType2.number + SuperType.name + SuperType.number); //TroyAlice321,321

寄生式继承（用于共享引用类型的值，与原型式类似）

var person = {
name: "Oliver",number: [13,21,31,1]
};

var anotherPerson = createAnother(person);
anotherPerson.number.pop();

console.log(anotherPerson.sayHi() + anotherPerson.number); //Hi13,31
console.log(person.number); //13,31

以上就是本文的全部内容，希望对大家的学习有所帮助。