JS: String.prototoype.match

By Xah Lee. Date: . Last updated: .

String.prototoype.match return a array, of captured groups, or, of all occurrences , depending on whether the RegExp argument has the global flag.

If the argument is a string, it is converted to a RegExp object.

Return a array of captured patterns. Index 0 is the whole matched string, index 1 is first captured pattern.

Return null if no match.

If there's the global flag g, return a array of all occurrences of matched string , or null if no match.

Get Captured Groups

Example of match without global flag. Get all captured groups.

// example of RegExp “match” method, capture groups
// capture the attribute values in a image tag
var xx = '<img class="pict" src="cat.jpg" alt="my cat" width="600" height="400">';

var result = xx.match(/<img class="([^"]+)" src="([^"]+)" alt="([^"]+)" width="([^"]+)" height="([^"]+)">/);

console.log(result[0]); // <img class="i" src="cat.jpg" alt="my cat" width="600" height="400">
console.log(result[1]); // pict
console.log(result[2]); // cat.jpg
console.log(result[3]); // my cat
console.log(result[4]); // 600
console.log(result[5]); // 400

Get All Occurrences

Example of match with global flag. Get all occurrences.

// example of RegExp “match” method
var xx = "google or yahoo for doodle";

console.log(
    xx.match(/.o+/g)    // [ 'goo', ' o', 'hoo', 'fo', 'doo' ]
);

console.log(
    xx.match(/x+/g)    // null
);

Reference

ECMAScript® 2016 Language Specification#sec-string.prototype.match

RegExp Topic

  1. JS: RegExp Tutorial
  2. JS: String Methods for RegExp
  3. JS: RegExp Object
  4. JS: RegExp Constructor
  5. JS: RegExp.prototype
  6. JS: RegExp Syntax

String Topic

  1. JS: Source Code Charset/Encoding
  2. JS: String Code Unit vs Code Point
  3. JS: Unicode Character Escape Sequence
  4. JS: Allowed Characters in Identifier
  5. HTML: Allowed Characters in id Attribute
  6. HTML: Character Sets and Encoding
  7. HTML/XML Entity List

  1. JS: Template String
  2. JS: Convert String to Number
  3. JS: Encode URL, Escape String
  4. JS: Format Number
  5. JS: JSON Object

  1. JS: String Object
  2. JS: String.prototype
  3. JS: String Constructor
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