js 普通对象继承

//非构造函数继承

    var persion = {
        age:24
    }
    
    var student = {
        identity:'student'
    }
    
    //1.object方法
    function object(o){
        function f(){};
        f.prototype = o;
        return new f();
    }
    
    var student = object(persion);
    console.log("identity:"+student.identity+" age:"+student.age);
    //这里的identity是undefined 因为student自己的属性被覆盖掉了，需要在继承后才加上自己的属性
    student.identity = "student";
    console.log("identity:"+student.identity+" age:"+student.age);
    
    //2浅拷贝方法
    function extendCopy(parent){
         var c = {};
        for(var i in parent){
            c[i] = parent[i];
        }
        return c;
    }
    
    /*
    这种方法如果遇到parent属性也是一个对象或数组的时候，
    属性值其实是一个内存地址，这样会出parent改变那个对象属性，继承的子类也会跟着变
    这样就不准了
     */
    
    //深拷贝——递归调用浅拷贝就能实现深拷贝
    function deepCopy(c,parent){
        var c = c||{};
        for(var i in parent){
            if(typeof c[i] == "ojbect"){
                c[i] = (parent[i].constructor === Array)?[]:{};
                deepCopy(c[i],parent[i]);
            }else{
                c[i] = parent[i];
            }
        }
        return c;
    }
    
    var a = {
        name:"a"
    }
    var p = {
        age:24,
        role:{code:404,msg:"msg"}
    }
    deepCopy(a,p);
    a.name = "I am a";
    console.log("name:"+ a.name+" code:"+ a.role.code+" msg:"+ a.role.msg+" age"+ a.age);

参考自：阮一峰