April 2020
Intermediate to advanced
177 pages
1h 45m
Chinese
Content preview from 精通模块化JavaScript
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126
｜
第
5
章
模块化模式与实践
5.2.3
在组合和继承之间进行选择
在实际开发中，除非需要连接到所依赖的特定框架、使用特定的模式（如
扩展原生的
JavaScript
数组），或者当性能被看作最重要的衡量因素时，否
则几乎不需要使用继承。当性能被作为使用原型的一个考量因素时，在匆
忙选择一种可能不那么理想的模式之前，对我们所做的假设进行测试并权
衡不同的方法，是非常有必要的。为了提高性能，我们可能会忽略很多因素。
装饰（
decoration
）和功能组合是更友好的模式，因为它们并不那么死板。
一旦你继承了某些东西，除非继续向原型链添加继承层，否则以后就不能
选择继承其他东西。当多个类继承自一个基类，但需要向外扩展，同时仍
然共享不同的功能部分时，这就成了一个问题。在这些情况以及许多其他
情况下，使用组合能让我们在不牺牲灵活性的前提下挑选所需要的功能。
与简单地改变对象或添加基类相比，函数式的方法实现起来有点麻烦，但
它提供了最大的灵活性。这种方法避免了对底层目标进行更改，使对象易
于序列化为
JSON
，不受不断增长的方法集的影响，因此更容易在代码库中
兼容。
此外，使用基类会使在原型链的不同插入点处重用逻辑变得有点困难。同样，
使用扩展函数，也会使添加类似方法来支持稍有不同的用例变得具有挑战
性。在这方面使用函数方法产生的耦合较少，但它也可能使对象构造的底
层实现变复杂，很难解释清楚它们的功能是如何联系在一起的，这会破坏
我们对代码流的基本理解，并使调试会话的时间变得更长。
与编程中的大多数道理一样，保持外观上的一致性对代码库是有好处的 ...
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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.