JavaScript: Find the first not repeated character

JavaScript Function: Exercise-23 with Solution

Write a JavaScript function to find the first not repeated character.

Sample arguments : 'abacddbec'
Expected output : 'e'

Pictorial Presentation:

JavaScript: Find the first not repeated character
Sample Solution: -

HTML Code:

<!DOCTYPE html>
  <meta charset="utf-8">
  <title>find the first not repeated character.</title>


JavaScript Code:

function find_FirstNotRepeatedChar(str) {
  var arra1 = str.split('');
  var result = '';
  var ctr = 0;
  for (var x = 0; x < arra1.length; x++) {
    ctr = 0;
    for (var y = 0; y < arra1.length; y++) 
      if (arra1[x] === arra1[y]) {
        ctr+= 1;
    if (ctr < 2) {
      result = arra1[x];
  return result;

Sample Output:



Flowchart: JavaScript function: Find the first not repeated character

Live Demo:

See the Pen JavaScript - Find the first not repeated character-function-ex- 23 by w3resource (@w3resource) on CodePen.

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Previous: 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.
Next: Write a JavaScript function to apply Bubble Sort algorithm.

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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