In JavaScript, a regular expression is an object, which can be defined in two ways. The rule of thumb is that simple regular expressions are simple to read and write, while complex regular expressions can quickly turn into a mess if you don’t deeply grasp the basics. This tutorial aims to introduce you to JavaScript Regular Expressions in a simple way, and give you all the information to read and create regular expressions. Regular expressions can appear like absolute nonsense to the beginner, and many times also to the professional developer, if one does not invest the time necessary to understand them.Ĭryptic regular expressions are hard to write, hard to read, and hard to maintain/modify.īut sometimes a regular expression is the only sane way to perform some string manipulation, so it’s a very valuable tool in your pocket. JavaScript, among with Perl, is one of the programming languages that have regular expressions support directly built in the language. Implemented in UNIX tools like grep, sed, and in popular text editors, regexes grew in popularity and were introduced in the Perl programming language, and later in many others. Regular Expressions date back to the 1950s, when it was formalized as a conceptual search pattern for string processing algorithms. Ranges of ASCII character codes may be abbreviated as in a-z0-9. There are small differences between each implementation, but the general concepts apply almost everywhere. A string enclosed in brackets matches any single character from the string.
How does a Regular Expression look like.