JavaScript: Extract unique characters from a string

JavaScript Function: Exercise-16 with Solution

Write a JavaScript function to extract unique characters from a string.

Example string : "thequickbrownfoxjumpsoverthelazydog"
Expected Output : "thequickbrownfxjmpsvlazydg"

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<meta charset=utf-8 />
<title>Extract unique character from a string</title>


JavaScript Code:

function unique_char(str1)
 var str=str1;
 var uniql="";
 for (var x=0;x < str.length;x++)

  uniql += str[x];  
  return uniql;  

Sample Output:



Flowchart: JavaScript function: Extract unique characters from a strin

Live Demo:

See the Pen JavaScript - Extract unique characters from a string-function-ex- 16 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript function to get the number of occurrences of each letter in specified string.

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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