如何用对象文字表示法创建方法？ [英] how to create a method in object literal notation?

问题描述

我已经在 Codeacademy.com 上开始了13天的网络编程，并且发现它是一个学习的好地方。但我有时还会误解事情。我总是在 w3school.com 上查看它们，但这次我找不到我需要的信息。因此，据我所知，首先有两种类型的创建对象：对象文字符号和第二种：对象构造函数。我已经了解到还有方法和函数，但我无法理解如何用对象文字表示法创建方法？在对象构造函数中，我只写：`

I have started web-programming for only 13 days on Codeacademy.com and find it a good place to learn. But I still sometimes misunderstand things. I always check them on w3school.com ,but this time I couldn't find the information that I needed. So as I learned there are 2 types of creating objects first: object literal notation and second: Object constructor. I have learned that there are also methods and functions, but I couldn't understand how to create a method in object literal notation? In object constructor I just write : `

var bob = new Object();
bob.age = 30;
bob.setAge = function (newAge)
{
bob.age = newAge;
};

在编写对象文字表示法时，能告诉我如何做同样的事。

Can you please tell me how to do the same when writing object literal notation.

var bob = {
age: 30
};

推荐答案

从语法上讲，变化非常简单：

Syntactically, the change is very simple :

var bob = {
  age: 30,
  setAge: function (newAge) {
    bob.age = newAge;
  }
};

但正如您所看到的，存在一个问题：在您的代码中它使用外部 bob 变量，所以如果你改变 bob 变量的值，这将不起作用。

But as you can see, there's a problem : as in your code it uses the external bob variable so this wouldn't work if you change the value of the bob variable.

您可以使用

var bob = {
  age: 30,
  setAge: function (newAge) {
    this.age = newAge;
  }
};

请注意，此时您应该检查您所需要的是否实际上一个类，如果你有几个可以带来一些性能改进实例。

Note that at this point you should check whether what you need isn't, in fact, a class, which would bring some performance improvements if you have several instances.

更新： ECMAScript 6现在允许以相同的方式定义方法，无论它们是否在对象文字中：

Update: ECMAScript 6 now allows methods to be defined the same way regardless of whether they are in an object literal:

var bob = {
  age: 30,
  setAge (newAge) {
    this.age = newAge;
  }
};

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