[翻译]High Performance JavaScript(017)
A Note on Benchmarking 测试基准说明
Because a regex's performance can be wildly different depending on the text it's applied to, there's no straightforward way to benchmark regexes against each other. For the best result, you need to benchmark your regexes on test strings of varying lengths that match, don't match, and nearly match.
因为正则表达式性能因应用文本不同而产生很大差异，没有简单明了的方法可以测试正则表达式之间的性能差别。为得到最好的结果，你需要在各种字符串上测试你的正则表达式，包括不同长度，能够匹配的，不能匹配的，和近似匹配的。
That's one reason for this chapter's lengthy backtracking coverage. Without a firm understanding of backtracking, you won't be able to anticipate and identify backtracking-related problems. To help you catch runaway backtracking early, always test your regexes with long strings that contain partial matches. Think about the kinds of strings that your regexes will nearly but not quite match, and include those in your tests.
这也是本章长篇大论回溯的原因之一。如果没有确切理解回溯，就无法预测和确定回溯相关问题。为帮助你早日把握回溯失控，总是用包含特殊匹配的长字符串测试你的正则表达式。针对你的正则表达式构思一些近似但不能完全匹配的字符串，将他们应用在你的测试中。
More Ways to Improve Regular Expression Efficiency 提高正则表达式效率的更多方法
The following are a variety of additional regex efficiency techniques. Several of the points here have already been touched upon during the backtracking discussion.
下面是一写提高正则表达式效率的技术。几个技术点已经在回溯部分讨论过了。
Focus on failing faster
关注如何让匹配更快失败
Slow regex processing is usually caused by slow failure rather than slow matching. This is compounded by the fact that if you're using a regex to match small parts of a large string, the regex will fail at many more positions than it will succeed. A change that makes a r
相关文档：
面向对象的语言多数都支持继承，继承最重要的优点就是代码复用，从而构建大型软件系统。如果一个类能够重用另一个类的属性和或方法，就称之为继承。
从这个角度来看看js的继承方式。js中继承方式与写类方式息息相关。不同的写类方式造成不同的继承方式。各种流行js库继承方式也各不相同。从最简单的
复用开始。
1、构造� ......
2、原型方式写类，原型方式继承
core js自身的对象系统就是采用原型方式(prototype based)继承的。或者说core
js没有采用常见的类继承(class
based)系统，而是使用原型继承来实现自己的对象系统。工作中我们也可以用原型方式来实现继承，代码复用以构建自己的功能模块。
/**
* 父类Polygon:多边形
*
*/
functio ......
第四章 Algorithms and Flow Control 算法和流程控制
The overall structure of your code is one of the main determinants as to how fast it will execute. Having a very small amount of code doesn't necessarily mean that it will run quickly, and having a large amount of code ......
Recursion Patterns 递归模式
When you run into a call stack size limit, your first step should be to identify any instances of recursion in the code. To that end, there are two recursive patterns to be aware of. The first is the straightforward recursive pattern represented ......
第五章 Strings and Regular Expressions 字符串和正则表达式
Practically all JavaScript programs are intimately tied to strings. For example, many applications use Ajax to fetch strings from a server, convert those strings into more easily usable JavaScript objects, and ......
