javascript - 通过 this 使用方法访问对象

Question

你能帮我解决这个代码吗？

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

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

我期望“macbook”登录控制台。

感谢您的帮助。

Answer 1

所以，这是执行您想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'));

查看您的原始代码:

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));