JavaScript继承: member functions not inheriting?

Question

这让我发疯。我快要崩溃并哭泣了。

这是我的代码，不起作用:

// parent class: Shirt
var Shirt = function() {
    this.basePrice = 1;
}
Shirt.prototype.getPrice = function(){return this.basePrice};
Shirt.prototype.display = function(){
    $('ul#products').append('<li>Product: $' + this.getPrice() + '.00</li>');
};

// subclass: ExpensiveShirt inherits from Shirt
var ExpensiveShirt = function() {
    this.basePrice = 5;
};
ExpensiveShirt.prototype = Object.create(Shirt);


// make some objects and test them
var s = new Shirt();
s.display();               // this works
console.log(s.getPrice()); // this works

var e = new ExpensiveShirt();
e.display();               // this does not work!
console.log(e.getPrice()); // does not work

HERE IS THE JSFIDDLE

现在，如果我添加这些行，那么它就可以工作:

ExpensiveShirt.prototype.getPrice = Shirt.prototype.getPrice;
ExpensiveShirt.prototype.display = Shirt.prototype.display;

但根据这个我不应该:JavaScript inheritance with Object.create()?我真的不想这样做，因为那是糟糕的编程。 >:(

Answer 1

Object.create期望新对象的原型(prototype)作为其参数，而不是构造函数。将您的行更改为此，它将起作用:

ExpensiveShirt.prototype = Object.create(Shirt.prototype);