//原型链
/*
只要是对象就有原型, 并且原型也是对象, 
因此只要定义了一个对象, 那么就可以找到他的原型,
如此反复, 就可以构成一个对象的序列, 这个结构就被成为原型链
*/
var Obj = function(){}; 
var o = new Obj(); 
o.__proto__ === Obj.prototype;  //=> true 
o.__proto__.constructor === Obj; //=> true
Obj.__proto__ === Function.prototype; //=> true 
Obj.__proto__.constructor === Function; //=> true
Function.__proto__ === Function.prototype; //=> true 
Object.__proto__ === Object.prototype;     //=> false 
Object.__proto__ === Function.prototype;   //=> true
Function.__proto__.constructor === Function;//=> true 
Function.__proto__.__proto__;               //=> {} 
Function.__proto__.__proto__ === o.__proto__.__proto__; //=> true 
o.__proto__.__proto__.__proto__ === null;   //=> true

    //call apply 继承
    /*父类*/
    function Parent(name, age) {
        this.name = name;
        this.age = age;
    }
    /*子类*/
    function Child(id) {
        this.id = id;
        //Parent.apply(this,["Sure",13])
        Parent.call(this, "Sure", 13);
        //这个时候的Parent中的this已经被Child所代替
    }
    var child = new Child("01");
    console.log(child.name)

//深拷贝
function deepClone(obj) { //递归拷贝
    if(obj == null) 
        return null;
    if(typeof obj !== 'object') 
        return obj
    let t = new obj.constructor();
    for(let key in obj) {
        t[key] = deepClone(obj[key]);
    }
    return t;
}

//自己写的深拷贝
let deepCopy = (data) => {
    let obj;
    if (typeof (data) != "object" || data == null) {
        obj = data;
    } else if (Array.isArray(data)) {
        obj = [];
        data.forEach(item => {
            obj[key] = deepCopy(item);
        })
    } else {
        obj = {};
        for (key in data) {
            obj[key] = deepCopy(data[key]);
        }
    }
    return obj;
}