How to count string occurrence in string using JavaScript ?

In JavaScript, we can count the string occurrence in a string by counting the number of times the string is present in the string. This can be done in the following ways:

• Using match() function
• Using loops
• Using split() function
• Using indexof() method

Approach 1: Using match() function:

match() function used to search a string for a match against any regular expression. If the match is found, then this will return the match as an array.

Example: Counting occurrence of Geeks in “GeeksforGeeks” using the “match()” function. 

Javascript

function gfg() {
    let r = "Geeks For Geeks ";
    console.log(
        (r.match(/Geeks/g)).length);

}
gfg()

Output

2

The ‘g’ in the function specifies global which is used to search for an entire string rather than stop by finding the first occurrence.

Approach 2: Using loop

Looping in programming languages is a feature that facilitates the execution of a set of instructions/functions repeatedly while some condition evaluates to true

Example: Counting occurrence of for in “GeeksforGeeks” using Loops. 

Javascript

function gfg() {
    let s = "Geeks for Geeks";
    let f = "for";
    let i = 0,
        n = 0,
        j = 0;

    while (true) {
        j = s.indexOf(f, j);
        if (j >= 0) {
            n++;
            j++;
        } else
            break;
    }
    console.log(n);
}
gfg()

Output

1

Approach 3: Using split() function

split() Method is used to split the given string into an array of strings by separating it into substrings using a specified separator provided in the argument.

Example: Counting occurrence of Geeks in “GeeksforGeeks” using split() function. 

Javascript

function gfg() {
    let s = "Geeks for Geeks";
    let f = "Geeks";
    let r = s.split(f).length - 1;
    console.log(r);
}
gfg()

Output

2

Approach 4: Using Indexof()

indexOf() method returns the position of the first occurrence of the specified character or string in a specified string.

Example: Counting occurrence of Geeks in “GeeksforGeeks” using indexof(). 

Javascript

function gfg() {
    let s = "Geeks for Geeks";
    let f = "Geeks";
    let r = s.indexOf(f);
    let c = 0;
    while (r != -1) {
        c++;
        r = s.indexOf(f, r + 1);
    }
    console.log(c);
}
gfg()

Output

2