JS: Regex Find/Replace

By Xah Lee. Date: . Last updated: .

Regex means Regular Expression. It is used to check if a string contains certain pattern, or extract the pattern, or replace it with other string. For example, extract email addresses in a text file.

For basic tutorial, see JS: RegExp Tutorial

There are 2 ways to use RegExp in JavaScript:

Following is a summary of the different methods.



Use this if you want to know position (index) of a pattern.

[see JS: String.prototype.search]


This method is used for one of two purposes.

[see JS: String.prototype.match]



Use this if you want to do string replacement.

[see JS: String.prototype.replace]



Return true or false.

Use this if you just want to know if a pattern matches.

[JS: RegExp.prototype.test]



Return a array of captured groups.

[JS: RegExp.prototype.exec]

JS RegExp

  1. RegExp Tutorial
  2. RegExp Syntax
  3. Regex Find/Replace

JS String

  1. String Overview
  2. Template String
  3. Char, Code Unit, Codepoint
  4. String Escape Sequence
  5. Unicode Escape Sequence
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