//function that takes an argument rawString and returns a sorted array of strings
function getTokens(rawString) {
  // NB: `.filter(Boolean)` removes any falsy items from an array

  //.toLowerCase() returns the lower case value of rawString
  //.split(/[ ,!.";:-]+/) splits the string into an array of substrings and a regular expression is used as the separator to separate the words of the string at any of the characters in the regex
  //now rawString is an array and .filter() method is used to create a new array with elements that pass the function Boolean which removes all falsy elements
  //then finally the .sort() method is used on the new array and sorts the array of strings by alphabetical order
  //a sorted array of strings with no falsy elements is returned by this function
  return rawString.toLowerCase().split(/[ ,!.";:-]+/).filter(Boolean).sort();
}

//function that takes an argument text and returns the updated most frequent word
function mostFrequentWord(text) {
  //declares a variable called words and sets its value to the returned value of the function getTokens
  let words = getTokens(text);

  //declares a variable called wordFrequencies and sets its value to an empty object
  let wordFrequencies = {};

  //a for loop is used to iterate through the array returned by getTokens(text)
  for (let i = 0; i <= words.length; i++) {

    //starting at index 0, if the element matches some key in wordFrequencies, then it will increment by one to the value of the key
    if (words[i] in wordFrequencies) {
      wordFrequencies[words[i]]++;
    }
    //else if the element does not match some key in wordFrequencies, then the element at words[i] will be added as a new key into wordFrequencies and its value will be set to 1
    else {
      wordFrequencies[words[i]] = 1;
    }
  }

  //declares a variable called currentMaxKey and sets its value to the key at index [0]
  let currentMaxKey = Object.keys(wordFrequencies)[0];

  //declares a variable called currentMaxCount and sets its value to the value of the key wordFrequencies[currentMaxKey]
  let currentMaxCount = wordFrequencies[currentMaxKey];

  //a for in loop that iterates through the keys in wordFrequencies
  for (let word in wordFrequencies) {

    //starting at the first key, if the value at wordFrequencies[word] is greater than the value at currentMaxCount, then currentMaxKey is set to word and the value at currentMaxCount is updated to the value at wordFrequencies[word]
    if (wordFrequencies[word] > currentMaxCount) {
      currentMaxKey = word;
      currentMaxCount = wordFrequencies[word];
    }
  }

  //the function should return the key with the highest value/count
  return currentMaxKey;
}