April 2020
Intermediate to advanced
177 pages
1h 45m
Chinese
Content preview from 精通模块化JavaScript
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68
｜
第
3
章
模块设计
模块中完成，有一点偏离最终的实现，但本质是相同的。二者最大的区别
在于，在得到想要的
API
之前，我们会反复写
README
文件，这一点其
实与
TDD
非常相似。不管怎样，
API
优先和
README
驱动设计都比直接
进入实现过程有明显的优势。
3.3.3
删除代码
对于
CSS
，有一种流行的描述是“只增加、不删除的语言（
append-only
language
）”，言下之意是如果你添加了一段
CSS
代码，就不能删除它了，
因为这样做可能会由于级联的原因无意中破坏程序的设计。
JavaScript
并
没有使删除代码变得非常困难，但它确实是一种高度动态的语言，并且在
JavaScript
中想要删除代码同时保证不会出现任何问题，仍然是一个挑战。
当然，修改模块的内部实现比更改它的公共
API
更容易，因为其影响仅限
于模块内部。不影响
API
而对模块内部进行的更改，通常从外部是看不出
来的。有一个例外，就是当使用者对我们的接口打猴子补丁（
monkey-patch
）
1
时，有时能观察到模块的一些内部信息。然而，在这种情况下使用者应该
意识到对模块打猴子补丁的脆弱性，这是他们无法控制的，并且需要自行
承担猴子补丁无法正常使用的风险。
在
3.1.2
节我们说过，最好的代码就是没有代码，这一条法则在删除代码时
也有意义。我们从没写过的代码是不需要担心删除的。代码越少，需要维
护的代码就越少，尚未发现的潜在
bug
就越少，需要阅读和测试的代码也少，
对移动网络速度要求高的人而言需要传输的代码就越少。
1
猴子补丁是从外部对组件的公共接口进行有目的的修改，以便添加、删除或更改其功能。当 ...
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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.