Tokenize a string consequetively and split into chunks

tokenizeStrAndSplitIntoChunks.js

const tokenizeStrAndSplitIntoChunks = (strToTokenize = '') =>
  [...strToTokenize].reduce(
    (acc, letter, i, { length }) => {
      if (/\w+/.test(letter)) {
        acc[acc.length - 1] += letter;
      } else if (i !== length - 1 && acc.at(-1) !== '') {
        acc.push('');
      }

      return acc;
    },
    ['']
  );
const myStr = `He is a very very good boy, isn't he?`;

if (/[A-Za-z!,?._'@]/.test(myStr)) {
  console.log(tokenizeStrAndSplitIntoChunks(myStr));
}

Explanation:

1. We split the given string by using spread operator first.
2. Then the split string becomes an array of string parts, thus we can safely use .reduce built-in method for it, with an initial value of one blank string!
3. While doing so, we iterate each letter and check if that item in the array is a string or digit by using \w regex character class.
   3.1. If it is, than we append that letter to the end of the previous str as seen in line 5.
   3.2 If not, **than we also check if the letter is NOT the last in the spreaded string ** and that last added item into the accumulator is not an empy string, because in the case of , (comma and blank consequetively), we'd end up adding an empty string without that condition.
4. Last but not least, we should always return the accumulator.