var letters = [ 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' ];
var leetChars = ['@', '8', '(', '|)', '3', 'ph', 'g', '#','l', '_|', '|<', '1', "|'|'|", '/\/', '0', '|D', '(,)', '|2', '5', '+', '|_|', '|/', "|/|/'",'><', 'j', '2'];


function translate(string) {
  // first, since all letter in array are lowercased, we will need to make our string lowercased.
  // we will need to create an empty string for the new leet word
  // next we will need to loop through each character of the string
  // for each character index, we will need to pull the letter index
  // then we will need to to pull the respective index from the leetChars array and add it to the new string

  var lowercased = string.toLowerCase();
  var leetString = '';
  var charIndex = null;

  for(var i = 0; i < lowercased.length; i++) {
    charIndex = letters.indexOf(lowercased[i]);
    leetString += leetChars[charIndex];
  }
  return leetString;
}

translate('Fullstack')    // => 'ph|_|115+@(|<'