通过此方法访问对象

Question

你能帮我这个代码吗？

var mac = {  
    notebook: "macbook",  
    desktop: "imac",  
    get_product: function (kind) {  
        return this.kind;  
    }  
}  

console.log(mac.get_product(notebook)); //ReferenceError: notebook is not defined

我希望“ macbook”能够登录到控制台。

感谢您的帮助。

Answer 1

因此，这是将执行您要执行的操作的代码：

var mac = {  
    notebook: "macbook",  
    desktop: "imac",  
    get_product: function (kind) {  
        return this[kind];  
    }  
}  

console.log(mac.get_product('notebook'));

查看原始代码：

var mac = {  
    notebook: "macbook",  
    desktop: "imac",  
    get_product: function (kind) {  
        // this.kind means mac.kind. You haven't defined mac.kind.
        // return this.kind;  
        // instead, you want to look up the value of the property defined
        // at kind.

        // [] allow you to dynamically access properties in JavaScript
        // this["<something>"] means "get me the property named <something>
        // but because the contents of [] are determined before the overall
        // expression, this is the same as return this["<something>"];
        // var prop = "<something>";  return this[prop];
        return this[kind];
    }  
}  
// notebook (without quotes) is interpreted as a variable, but there is no
// variable by the name "notebook".
console.log(mac.get_product(notebook));

Answer 2

notebook是mac内部的，因此您不能在console.log(mac.get_product(notebook));上访问它console.log(mac.get_product(notebook));

看一下这篇文章： http : //javascriptissexy.com/understand-javascripts-this-with-clarity-and-master-it/

Answer 3

就像get_product函数一样， notebook参数也在变量mac中定义-因此您需要将其称为mac.notebook 。

Answer 4

有一些事情要解决。

1. 没有“笔记本”（它是“ mac.notebook”）之类的东西，

2. 没有“ this.kind”这样的东西（我想你的意思是“ this.notebook”）。

    var mac = { notebook: "macbook", desktop: "imac", get_product: function (kind) { return this.notebook; } } console.log(mac.get_product(mac.notebook));