Question

Some people, when confronted with a problem, think ‘I know, I’ll use regular expressions.’ Now they have two problems.

Jamie Zawinski

Programming tools and techniques survive and spread in a chaotic, evolutionary way. It’s not always the pretty or brilliant ones that win but rather the ones that function well enough within the right niche—for example, by being integrated with another successful piece of technology.

In this chapter, I will discuss one such tool, regular expressions. Regular expressions are a way to describe patterns in string data. They form a small, separate language that is part of JavaScript and many other languages and tools.

Regular expressions are both terribly awkward and extremely useful. Their syntax is cryptic, and the programming interface JavaScript provides for them is clumsy. But they are a powerful tool for inspecting and processing strings. Properly understanding regular expressions will make you a more effective programmer.

This is a book about getting computers to do what you want them to do. Computers are about as common as screwdrivers today, but they contain a lot more hidden complexity and thus are harder to operate and understand. To many, they remain alien, slightly threatening things.