September 2022
Intermediate to advanced
585 pages
8h 17m
Chinese
Content preview from JavaScript 经典实例：第三版
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201
第
8
章
类
JavaScript
是一门面向对象的编程语言吗？这要看你问谁（以及你是如何表述的）。
不过，普遍的共识是肯定的，但也有一些需要注意的地方。
在学术界之外，面向对象编程语言通常围绕类、接口和继承等概念展开。可是直到
最近，
JavaScript
还是一个异类，一门建立在函数和原型之上的面向对象编程语言。
随着
ES6
的出现，突然之间，类变成了这门语言的原生结构，水又浑浊了起来。类
仅仅是一种语法糖，还是语言的巨大进步？
答案介于两者之间。总的来说，
ES6
类是一种高级语言特性，建立在我们熟悉的
JavaScript
原型之上。但是二者之间没有对等关系，类模型引入了一些新的特性，与
原型模型相比有微妙的差异，不完全相同。此外，类在未来可能会支持新的面向对
象特性，进一步拉开两种模型的差距。
目前的状况是，新项目开发喜欢使用类，但是基于原型的代码依然常见（而且远未
过时）。本章重点介绍类的常用模式，不过也涉及原型。
8.1
创建一个可重用的类
8.1.1
问题
你想为自定义的对象创建一个可重用的模板。
202
｜
第
8
章
8.1.2
方案
使用
class
关键字，为类起一个名称。在类内部添加一个构造函数，用于初始化对象。
下面是一个完整的
Person
类示例。
class
Person {
constructor(firstName, ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.