longest sub string

by Kai Wang

JavaScript

var lengthOfLongestSubstring = function(s) {
  var longest = [];
  var current = [];
  s.forEach(d=> {
    if (current.indexOf(d) < 0) {
      current.push(d)
    } else {
      current = [d];
    }
    if (current.length > longest.length) {
      longest = current.slice(0);
    }

  })
  return longest;
};

var a = "abjkfhkjafkkdnchasjfd";
var b = lengthOfLongestSubstring(a);
console.log(b)