JS中的继承

一、原型继承

function surperClass () {
    this.name= 'hello';
}
surperClass.prototype.getSurperName = function(){
    return this.name;
};

function subClass(name){
    this.name = 'world';
}
//继承了surperClass
subClass.prototype = new surperClass();
subClass.prototype.getsubClassName = function(){
    return this.name;
};

var instance = new subClass();
console.log(instance.getSurperName);  //hello

原型链虽然很强大，可以用它来实现继承，但它也存在一些问题。在通过原型来实现继承时，原型实际上会变成另一个类型的实例。于是，原先的实例也就顺理成章地变成了现在的原型属性了

二、借用构造函数继承

function surperClass(name){
    this.name = name;
    this.color = ['red','white','yellow'];
}
function subClass(){
    surperClass.call(this,'goodnight');
}
var instance = new subClass();
instance.push('blue');
alert(instance.color); // red ,white,yellow ,blue

var instance2 = new subClass();
alert(instance2.color); // red white yellow

三、组合继承

function surperClass(name){
    this.name = name;
    this.color = ['red','white','yellow'];
}
surperClass.prototype.getName = function(){
    // body... 
    return name;
};
function subClass(age){
    surperClass.call(this,'goodnight');
    this.age = age;
}
subClass.prototype = new surperClass();
subClass.prototype.getAge = function(){
    // body... 
    return this.age;
};
var instance = new subClass(23);
alert(instance.getName()); //goodnight
alert(instance.getAge());   // 23

四、原型式继承

function object (o) {
    function f () {
        // body... 
    }
    f.prototype = o;
    return new f();
}
var persion = {
    name:'nick',
    friends:['lily','Rob']
}

var anotherpersion = Object(persion);
anotherpersion.name; //'nick'
anotherpersion.friends.push('134');

alert(persion.friends) //lily rob 134

五、寄生式继承

function object (o) {
    function f () {
        // body... 
    }
    f.prototype = o;
    f.getName = function () {
        /* body... */
    }
    return new f();
}

六、寄生组合式继承

function inhreitProperty (subClass,surperClass) {
    // body... 
    //复制一份父类的原型副本保存在P中
    var p = object(surperClass.prototype);
    //修正因为重写子类原型导致子类的constructor属性被修改
    p.constructor = subClass;
    //设置子类的原型
    subClass.prototype = p;
}