return the first non repeating character in a string in javascript

Question

So I tried looking for this in the search but the closest I could come is a similar answer in several different languages, I would like to use Javascript to do it.

T

Answer 1

I came accross this while facing similar problem. Let me add my 2 lines. What I did is a similar to the Guffa's answer. But using both indexOf method and lastIndexOf.

My mehod:

function nonRepeated(str) {
   for(let i = 0; i < str.length; i++) {
      let j = str.charAt(i)
      if (str.indexOf(j) == str.lastIndexOf(j)) {
        return j;
      }
   }
   return null;
}

nonRepeated("aabcbd"); //c

Simply, indexOf() gets first occurrence of a character & lastIndexOf() gets the last occurrence. So when the first occurrence is also == the last occurence, it means there's just one the character.