text: 'use strict';
  
  var letterScores = {
    'a': 1, 'e': 1, 'i': 1, 'o': 1,
    'u': 1, 'l': 1, 'n': 1, 'r': 1,
    's': 1, 't': 1, 'd': 2, 'g': 2,
    'b': 3, 'c': 3, 'm': 3, 'p': 3,
    'f': 4, 'h': 4, 'v': 4, 'w': 4,
    'y': 4, 'k': 5, 'j': 8, 'x': 8,
    'q': 10, 'z': 10
  };
  
  function letterScore(letter) {
    return letterScores[letter] || 0;
  }
  
  module.exports = function (wrd) {
    var word = wrd ? wrd.toLowerCase() : '';
  
    var sum = 0;
    var idx = -1;
    var end = word.length;
  
    while (++idx < end) {
      sum += letterScore(word[idx]);
    }
  
    return sum;
  };
  