理解js对象继承的N种模式
时间：2021-11-14 10:25:08|栏目：JavaScript代码|点击： 次
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
function Person(){};
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
function SuperType(){
this.color = ["red","yellow","white"];
}
function SubType(){
SuperType.call(this);
}
var instance1 = new SubType();
var instance2 = new SubType();
instance1.color.pop();
console.log(instance1.color); //["red", "yellow"]
console.log(instance2.color); //["red", "yellow", "white"]
2、有参数
function SuperType(name){
this.name = name;
this.number = [21,32,14,1];
}
function SubType(name,age){
SuperType.call(this,name);
this.age = age;
}
var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);
instance2.number.pop();
console.log(instance1.name + instance1.age + instance1.number); //Oliver1821,32,14,1
console.log(instance2.name + instance2.age + instance2.number); //Troy2421,32,14
三、组合继承（伪经典继承）
1、无参数
function SuperType(){
this.color = ["red","yellow","white"];
}
SuperType.prototype.sayColor = function(){
return this.color;
};
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 SuperType(name){
this.name = name;
this.number = [32,1342,11,1];
}
SuperType.prototype.sayName = function(){
return this.name;
};
function SubType(name,age){
SuperType.call(this,name);
this.age = age;
}
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
SubType.prototype.sayAge = function(){
return this.age;
};
var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);
instance2.number.pop();
console.log(instance1.sayName() + instance1.sayAge() + instance1.number); //Oliver1832,1342,11,1
console.log(instance2.sayName() + instance2.sayAge() + instance2.number); //Troy2432,1342,11
三、寄生组合式继承（引用类型最理想的范式）
function inheritPrototype(subType,superType){
var prototype = Object(superType.prototype);
prototype.constructor = subType;
subType.prototype = prototype;
}
function SuperType(name){
this.name = name;
this.number = [321,321,43];
}
SuperType.prototype.sayName = function(){
return this.name;
};
function SubType(name,age){
SuperType.call(this,name);
this.age = age;
}
inheritPrototype(SubType,SuperType);
SubType.prototype.sayAge = function(){
return this.age;
};
var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);
instance2.number.pop();
console.log(instance1.sayName() + instance1.sayAge() + instance1.number); //Oliver18321,321,43
console.log(instance2.sayName() + instance2.sayAge() + instance2.number); //Troy24321,321
或者可以把inheritPrototype 函数写成下面这样：
function inheritPrototype(SubType,SuperType){
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
}
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）
function object(o){
function F(){};
F.prototype = o;
return new F();
}
var SuperType = {
name: "Oliver",
number: [321,321,4532,1]
};
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 SuperType = {
name: "Oliver",
number: [321,321,4532,1]
};
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); //TroyAlice321,321321,321Oliver321,321
ECMAScript 5 简写版（定义Object.create()的第二个参数，再继承）
var SuperType = {
name: "Oliver",
number: [321,321,4532,1]
};
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); //TroyAlice321,321321,321Oliver321,321
寄生式继承（用于共享引用类型的值，与原型式类似）
function createAnother(original){
var clone = Object(original);
clone.sayHi = function(){
return "Hi";
};
return clone;
}
var person = {
name: "Oliver",
number: [13,21,31,1]
};
var anotherPerson = createAnother(person);
anotherPerson.number.pop();
console.log(anotherPerson.sayHi() + anotherPerson.number); //Hi13,21,31
console.log(person.number); //13,21,31
以上就是本文的全部内容，希望对大家的学习有所帮助。
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栏 目：JavaScript代码
本文标题：理解js对象继承的N种模式
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