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