The match() method in JavaScript is used for identifying and retrieving substrings that fit a specified pattern, defined by a regular expression. It is often used when you need to find particular patterns within strings, enabling efficient text processing.

This method returns an array of matched substrings or null if no match is found.

Syntax:

string.match(regExp);

Parameters:

• string: The string to be searched for a specific pattern.
• regexp: A regular expression object or pattern string used to search the string.

Note: If the g flag is not used with the regular expression, only the first match will be returned. If the g flag is used, all matches will be returned.

Return Value:

• Array: An array of matched substrings if matches are found.
• null: If no match is found, the method returns null.

Example 1: Using the /g Flag (Global)

The global (g) flag ensures that all occurrences of the matching pattern are returned. Below is an example that matches the substring "eek" multiple times in the string:

// Initializing function to demonstrate match()
// method with "g" para
function matchString() {
    let string = "Welcome to geeks for geeks";
    let result = string.match(/eek/g);
    console.log("Output : " + result);
} matchString(); 

Example 2: Using the /i Flag (Case-Insensitive)

The case-insensitive (i) flag allows the match() method to ignore letter case when matching patterns. Here is an example:

// Initializing function to demonstrate match()
// method with "i" para
function matchString() {
    let string = "Welcome to GEEKS for geeks!";
    let result = string.match(/eek/i);
    console.log("Output : " + result);
} matchString();

Example 3: Using the /gi Flag (Global and Case-Insensitive)

When both the global (g) and case-insensitive (i) flags are used together, the match() method will find all case-insensitive matches throughout the string. Below is an example:

// Initializing function to demonstrate match()
// method with "gi" para
function matchString() {
    let string = "Welcome to GEEKS for geeks!";
    let result = string.match(/eek/gi);
    console.log("Output : " + result);
} matchString();   

We have a complete list of Javascript string methods, to check those please go through this Javascript String Complete reference article.