Punctuation helper

punctuate.js

const punctuate = (items = []) => {
  const amount = items.length;

  return items.reduce((acc, item, index) => {
    if (amount === 1) {
      return item;
    }

    return index === (amount - 1)
      ? `${acc} and ${item}`
      : `${acc}, ${item}`;
  }, '');
};