javascript - Javascript 继承代码学院

Question

使用下面给出的代码，我正在尝试输出 choc 的值和类型，而巧克力的类型和牛奶却未定义。有人可以帮我理解如何输出类型吗？我已经为此工作了一段时间，但它并没有点击我。谢谢！

// we set up a base class
function Candy() {
    this.sweet = true;
}

// create a "Chocolate" class with a "type" argument
Chocolate = function(type){
    this.type = type;
};

// say that Chocolate inherits from Candy

Chocolate.prototype = new Candy();

// create a "choc" object using the Chocolate constructor 
// that has a "type" of "milk"

var choc = new Object();
choc.type = "milk";

// print the sweet and type properties of choc
console.log(choc.sweet);
console.log(choc.type);

//////这是我改成的，还是不行//////////

// we set up a base class
function Candy() {
    this.sweet = true;
}

// create a "Chocolate" class with a "type" argument
Chocolate = function(type){
    this.type = type;
};

// say that Chocolate inherits from Candy

Chocolate.prototype = new Candy();

// create a "choc" object using the Chocolate constructor 
// that has a "type" of "milk"

var choc = new Chocolate();
choc.type = "milk";

// print the sweet and type properties of choc
console.log(choc.sweet);
console.log(choc.type);

Answer 1

查看代码的最后四行（它不使用上面的任何内容）：

// create a "choc" object using the Chocolate constructor 
// that has a "type" of "milk"

var choc = new Object();
choc.type = "milk";

// print the sweet and type properties of choc
console.log(choc.value);
console.log(choc.type);

您既没有创建Chocolate对象，也没有打印sweet属性（因此得到undefinedfor value）。

相反，使用

var choc = new Chocolate("milk");
console.log(choc.sweet); // true
console.log(choc.type); // "milk"

您更新的代码对我有用。