JavaScript: Letter count within a string

JavaScript Function: Exercise-22 with Solution

Write a JavaScript function that accepts two arguments, a string and a letter and the function will count the number of occurrences of the specified letter within the string.

Sample arguments: 'w3resource.com', 'o'
Expected output: 2

Pictorial Presentation:

JavaScript: Letter count within a string

Sample Solution: -

HTML Code:

<!DOCTYPE html>
  <meta charset="utf-8">
  <title>Letter count within a string</title>


JavaScript Code:

function char_count(str, letter) 
 var letter_Count = 0;
 for (var position = 0; position < str.length; position++) 
    if (str.charAt(position) == letter) 
      letter_Count += 1;
  return letter_Count;

console.log(char_count('w3resource.com', 'o'));

Sample Output:



Flowchart: JavaScript function: Letter count within a string

Live Demo:

See the Pen JavaScript - Letter count within a string-function-ex- 22 by w3resource (@w3resource) on CodePen.

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Previous: Write a JavaScript function to get all possible subset with a fixed length (for example 2) combinations in an array.
Next: Write a JavaScript function to find the first not repeated character.

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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";


includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv