新手求助：为什么这里的Console.log返回undefined？

Question

function d(){this.get=function(){this.getNum()}};
d.prototype.getName=function(){return 3;};
var d = new d();
console.log(d.get());//undefined

为什么这里显示undefined？而不是3？求解答

Answer 1

function d(){this.get=function(){return this.getName()}};
d.prototype.getName=function(){return 3;};
var d = new d();
console.log(d.get());//undefined

Answer 2

function d(){this.get=function(){return this.getNum()}};

你说呢

Answer 3

function d(){this.get=function(){return this.getName();}};
d.prototype.getName=function(){return 3;};
var d = new d();
console.log(d.get());

自己对比下

Answer 4

num name

Answer 5

this.getnum改成this.getname

Answer 6

function d(){
            this.get= function(){
                return this.getName()
            }
        };
        d.prototype.getName = function(){
            return 3;
        };
        var d = new d();
        console.log(d.get());