function getTokens(rawString) {
//BB: This function returns a sorted array of all words in rawString
  // NB: `.filter(Boolean)` removes any falsy items from an array
  return rawString.toLowerCase().split(/[ ,!.";:-]+/).filter(Boolean).sort();
}

function mostFrequentWord(text) {
  let words = getTokens(text); // BB: get sorted array of all words in 'text'
  let wordFrequencies = {}; // BB: init object -- list of keys (words) and frequencies

  // BB: loop through each word
  //     if word not already a key,
  //     add the key and set its value to 1,
  //     otherwise increment its value by 1
  for (let i = 0; i <= words.length; i++) {
    if (words[i] in wordFrequencies) {
      wordFrequencies[words[i]]++;
    } else {
      wordFrequencies[words[i]] = 1;
    }
  }

  // BB: init "most frequent word/key" and count vars:
  let currentMaxKey = Object.keys(wordFrequencies)[0];
  let currentMaxCount = wordFrequencies[currentMaxKey];

  // BB: for each key in wordFrequencies, compare its count
  //     to the max count, and if it's greater, set the
  //     MaxKey and MaxCount to this Key and Count
  for (let word in wordFrequencies) {
    if (wordFrequencies[word] > currentMaxCount) {
      currentMaxKey = word;
      currentMaxCount = wordFrequencies[word];
    }
  }
  // BB: return the result of the MaxKey
  //     (word with greatest frequency)
  return currentMaxKey;
}