gistfile1.txt

function dictionaryToWords(text) {
  if (text === '') return { };
  var map = { };
  var words = text.split(' ').filter(function(word) { return word !== ""; }); //  [ I, *will*, fight, to, follow, I, will, fight, for, *love* ]
  
  for (var i = 0; i < words.length; i++) {
    var currentWord = words[i];
    
    // map["love"] === undefined
    
    // the first case: currentWord is a new word => it is not in the map
    if (!map[currentWord]) {
      if ((i + 1) < words.length) {
        map[currentWord] = [ words[i + 1] ];
      }
      else {
        map[currentWord] = [];
      }
      
      /*map[currentWord] = ((i + 1) < words.length 
        ? [ words[i + 1] ] 
        : []
      );*/
    }
    else {
      // the second case: currentWord is an existing word => it is in the map
      var followingWords = map[currentWord];  // fight: ['for']
      
      // there is a next word after currentWord
      if ((i + 1) < words.length) {
        var nextWord = words[i + 1];
        
        if (!followingWords.some(value => value === nextWord)) {
          followingWords.push(nextWord); // fight: ['for', 'to']
        }
      }
    }
  }
  
  return map;
}