Regular expressions in JavaScript are a powerful way to search, match, and manipulate strings. In this guide, we will focus on the key methods associated with regular expressions, providing a detailed explanation and example for each. Understanding these methods will allow you to efficiently handle pattern matching in your JavaScript code.

RegExp.test()

The test() method executes a search for a match between a regular expression and a specified string. It returns true or false.

Example

In this example, the test() method checks if the string "Hello world!" contains the pattern "hello". Since the method is case-sensitive, it returns false.

RegExp.exec()

The exec() method executes a search for a match in a specified string. It returns an array of matched results or null if no match is found.

Example

In this example, the exec() method finds a match for one or more digits in the string "The year is 2024." and returns an array with the matched result.

String.search()

The search() method executes a search for a match between a regular expression and a specified string. It returns the index of the first match, or -1 if no match is found.

Example

In this example, the search() method returns the index of the first occurrence of "awesome" in the string, which is 16.

String.split()

The split() method divides a string into an ordered list of substrings by searching for a pattern, and returns the substrings in an array.

Example

In this example, the split() method uses a comma as the delimiter to split the string into an array of substrings.

String.match()

The match() method retrieves the result of matching a string against a regular expression.

Example

In this example, the match() method finds all occurrences of the pattern "ain" in the string and returns them in an array.

String.matchAll()

The matchAll() method returns an iterator of all results matching a string against a regular expression, including capturing groups.

Example

In this example, the matchAll() method returns an iterator of all matches for the pattern "t(e)(st(\d?))" in the string "test1test2", including capturing groups.

Conclusion

This guide provides a focused and detailed look at the primary methods used with regular expressions in JavaScript, complete with practical examples. These methods are essential tools for developers working with string manipulation and pattern matching.