42 lines
945 B
Markdown
42 lines
945 B
Markdown
# 对象和类
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## 对象
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JavaScript中的对象(object)用于存储各种键值集合和更复杂的实体。例如下面的对象
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```javascript :no-line-numbers
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var person = {
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firstName: 'John',
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lastName: 'Doe',
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age: 30,
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isStudent: false,
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greet: function() {
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console.log('Hello, I am ' + this.firstName + ' ' + this.lastName);
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}
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print_name() {
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console.log(lastName + ' ' + firstName)
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}
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};
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```
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如何使用对象
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```javascript :no-line-numbers
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console.log(person.firstName); // 输出: John
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person.greet(); // 输出: Hello, I am John Doe
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```
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## 类
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javascript中的类(class)是用于创建对象的模板，和c++中的类相似，但是需要在`constructor()`函数中声明类成员
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```javascript :no-line-numbers
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class User {
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constructor(name) {
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this.name = name;
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}
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greet() {
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console.log("Hello, I'm " + this.name)
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}
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}
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```
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使用方法
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```javascript :no-line-numbers
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var user = new User("Alice")
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user.greet()
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``` |