在JavaScript中使用继承模式 [英] Using inheritance patterns in JavaScript

问题描述

根据我的经验，JavaScript会这样做：

From my experiance, JavaScript does this:

• 操纵DOM或其​​他主机对象


• 添加事件处理程序


• 执行Ajax

因为我开始深入研究原型继承，我会想知道它在实践中是如何实际使用的。有什么用例？

Since I started digging into prototypal inheritance, I would like to know how it is actually used in practice. What are the use cases?

有人在这里积极使用继承模式吗？为什么？

Is anyone here actively using inheritance patterns? What for?

（我知道我的问题有很多答案 - 我只想听听其中的一些，以便在JavaScript中使用继承的感觉）

(I understand that there are lots of answers to my question - I just would like to hear some of them to get the feel of using inheritance in JavaScript)

推荐答案

我使用jQuery（和之前的JavaScript）的经验是原型继承没有我想象的那么有用。它有用，但它对语言并不重要。

My experience working with jQuery (and JavaScript before it) is that prototypical inheritance isn't as useful as I was expecting. It has uses, but it's not fundamentally important to the language.

在Javascript中，如果你想用方法返回一个对象 foo ：

In Javascript if you want to return an object with a method foo:

return { 
  foo: function() { 
    alert('You called foo!'); 
  }
};

调用者可以将这些对象视为多态 - 也就是说，他们可以调用 foo 而不用担心它的类型对象。不需要继承。

And callers can treat such objects as polymorphic - that is, they can call foo without worrying about what "type" of object it is. There is no need for inheritance.

在这种背景下，原型只是一种优化。它们允许您创建大量对象，而无需在每个实例中复制大量函数属性。这就是jQuery在内部使用它的原因。 jQuery对象有许多函数，将它们复制到每个实例可能是一个很大的开销。

Against this background, prototypes are merely an optimisation. They allow you to create a large number of objects without having to replicate a big set of function properties in each instance. This is why jQuery uses it internally. A jQuery object has dozens of functions, and it might be a major overhead to copy them into every instance.

但是从jQuery用户的角度来看，原型并不是'特别重要。它可以被重写为不使用它们，它仍然可以工作（但可能会使用更多的内存）。

But from the perspective of a user of jQuery, prototypes aren't particularly important. It could be rewritten to not use them and it would still work (but might use a lot more memory).

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