September 2022
Intermediate to advanced
585 pages
8h 17m
Chinese
Content preview from JavaScript 经典实例：第三版
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.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.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.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.
类
｜
223
与构造函数不同，静态方法的数量不受限制，你可以根据创建对象的需要，添加任
意多个静态函数。
有时，这种静态方法叫作工厂方法（
factory method
），不过严格来说这个
名称并不贴切。在面向对象设计理论中，当你不知道要创建的对象是什么类
型时才使用工厂模式。例如，你可以定义一个
createBook()
方法，根据提
供的参数决定返回
TechBook
类的实例还是
FictionBook
类的实例（这两个
类都继承
Book
类）。在
JavaScript
中也可以实现这个设计模式，但是人们
对于这门语言怎样才能完好处理这种典型的
OOP
抽象还没有统一意见。
8.8
从其他类继承功能
8.8.1
问题
你想自定义一个类，从其他类继承功能。
8.8.2
方案
子类通过继承衍生自父类。在代码中，声明子类时通过
extends
关键字表明继承。
public class
SomeChild
extends
SomeParent {
}
下述示例中的
Triangle
类继承自一个更一般的父类，名为
Shape
。
//
这是父类
class
Shape {
getArea() {
return null
;
}
}
//
这是一个子类
224
｜
第
8
章
class
Triangle extends Shape {
constructor(base, ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.