72 lines
1.7 KiB
Markdown
72 lines
1.7 KiB
Markdown
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---
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title: Object Instantiation
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localeTitle: 对象实例化
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---
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## 对象实例化
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在Javascript和大多数其他语言中，对象包含一系列属性，这些属性是键值对。当您需要构造对象时，可以使用多个选项。
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### 初始化对象变量
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您可以创建具有预定义属性的对象，如下所示：
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```javascript
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let myObject = {
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name: "Dave",
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age: 33
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}
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```
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### 创建一个空对象
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这会在myObject变量中创建一个空对象：
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```javascript
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let myObject = new Object();
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```
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当您希望向对象添加属性时，只需使用点表示法或括号表示法以及您选择的属性名称：
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```javascript
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myObject.name = "Johnny Mnemonic"
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myObject["age"] = 55
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```
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### 使用构造函数
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您可以定义可用于创建对象的构造函数：
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```javascript
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function Kitten(name, cute, color) {
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this.name = name,
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this.cute = cute,
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this.color = color
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}
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```
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您可以通过调用构造函数来定义包含此对象实例化的变量：
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```javascript
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let myKitten = new Kitten("Nibbles", true, "white")
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```
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### 的Object.create（）
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Object.create（）方法（首先在ECMAScript 5.1中定义）允许您创建对象。它允许您为新对象选择原型对象，而无需事先定义构造函数。
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```javascript
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// Our pre-defined object
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let kitten = {
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name: "Fluff",
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cute: true,
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color: "gray"
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}
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// Create a new object using Object.create(). kitten is used as the prototype
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let newKitten = Object.create(kitten)
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console.log(newKitten.name) // Will output "Fluff"
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```
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#### 更多信息
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[关于使用对象的MDN文章](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects)
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