JS String Prototype Match

JavaScript String prototype match

The match() method retrieves the matches when matching a string against a regular expression.

Syntax

str.match(regexp)

Parameters

regexp

A regular expression object. If a non-RegExp object obj is passed, it is implicitly converted to a RegExp by using new RegExp(obj).

MDN link | MSDN link

Returns

An Array containing the matched results or null if there were no matches.

Description

If the regular expression does not include the g flag, returns the same result as RegExp.exec(). The returned Array has an extra input property, which contains the original string that was parsed. In addition, it has an index property, which represents the zero-based index of the match in the string.

If the regular expression includes the g flag, the method returns an Array containing all matched substrings rather than match objects. Captured groups are not returned. If there were no matches, the method returns null.

Examples

var str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
var regexp = /[A-E]/gi;
var matches_array = str.match(regexp);

console.log(matches_array);
// ['A', 'B', 'C', 'D', 'E', 'a', 'b', 'c', 'd', 'e']

var str = 'For more information, see Chapter 3.4.5.1';
var re = /(chapter \d+(\.\d)*)/i;
var found = str.match(re);

console.log(found);

// logs ['Chapter 3.4.5.1', 'Chapter 3.4.5.1', '.1']

// 'Chapter 3.4.5.1' is the first match and the first value 
// remembered from `(Chapter \d+(\.\d)*)`.

// '.1' is the last value remembered from `(\.\d)`.