Question

How to remove all duplicate characters from a string in JavaScript

Answer 1

function remove_duplicate_characters(s) {
  return s
    .split('')
    .filter(function(item, pos, self) {
        return self.indexOf(item) === pos;
    })
    .join('');
}
 
 
  
let s = "javaaaaascripttttt prooooogramminggggg";
 
s = remove_duplicate_characters(s);
 
console.log(s); 
 
 
 
/*
run:
     
javscript ogmn
  
*/  

 

70+ SQL courses for beginners and professionals

Answer 2

function remove_duplicate_characters(s) {
    let arr = [];
    let result = '';
 
    for (let i = 0; i < s.length; i++) {
        if (!(s[i] in arr)) {
            result += s[i];
            arr[s[i]] = true;
        }
    }
    
    return result;
}

let s = "javaaaaascripttttt prooooogramminggggg";
 
s = remove_duplicate_characters(s);
 
console.log(s); 
 
 
 
/*
run:
     
javscript ogmn
  
*/

 

70+ SQL courses for beginners and professionals

Answer 3

let str = "javaaaaascripttttt prooooogramminggggg";
 
str = [...new Set(str)].join('');
  
console.log(str); 

 
 
/*
run:
     
javscript ogmn
  
*/

 

70+ SQL courses for beginners and professionals