JS: Regex Find/Replace

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:

• String.prototype methods for regex. [see JS: String.prototype]
• RegExp.prototype methods. [see JS: RegExp.prototype]

Following is a summary of the different methods.

String.prototype.search

str.search(/pattern/)

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

[see JS: String.prototype.search]

String.prototype.match

• str.match(/…/g) → return all occurrences of matched string.
• str.match(/…/) → return captured patterns.

This method is used for one of two purposes.

• Get all substrings that match the pattern.
• Get all substrings that match the captured groups in pattern.

[see JS: String.prototype.match]

String.prototype.replace

str.replace(regex,replace_str_or_func)

Use this if you want to do string replacement.

[see JS: String.prototype.replace]

RegExp.prototype.test

regex.test(string)

Return true or false.

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

[JS: RegExp.prototype.test]

RegExp.prototype.exec

regex.exec(string)

Return a array of captured groups.

[JS: RegExp.prototype.exec]