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.

The problem is I have an arbitrary string that I would like to return the first non repeating character. EX: 'aba' -> would return b 'aabcbd' -> would return c. This is what I have so far, just a simple for loop to start.

var someString = 'aabcbd';



var firstNonRepeatedCharacter = function(string) {
for(var i = 0; i < someString.length; i++){

}
};

http://jsfiddle.net/w7F87/ Not sure where to go from here

Answer 1

You can use the indexOf method to find the non repeating character. If you look for the character in the string, it will be the first one found, and you won't find another after it:

function firstNonRepeatedCharacter(string) {
  for (var i = 0; i < string.length; i++) {
    var c = string.charAt(i);
    if (string.indexOf(c) == i && string.indexOf(c, i + 1) == -1) {
      return c;
    }
  }
  return null;
}

Demo: http://jsfiddle.net/Guffa/Se4dD/