Converts a string to title case

titleCase.js

function titleCase (title) {
  const smallWords = [
    'a',
    'an',
    'and',
    'at',
    'but',
    'by',
    'else',
    'for',
    'from',
    'if',
    'in',
    'into',
    'is',
    'nor',
    'of',
    'off',
    'on',
    'or',
    'out',
    'over',
    'the',
    'then',
    'to',
    'when',
    'with'
  ];

  const specialWords = [
    'I',
    'II',
    'III',
    'IV',
    'V',
    'VI',
    'VII',
    'UK',
    'US'
  ];

  const punctuation = [
    '.',
    '-',
    ':',
    '!',
    '?'
  ];

  let words = title.toLowerCase().split(' ');

  for (let i = 0; i < words.length; i++) {
    let word = words[i];
    let lastCharacterPreviousWord = words[i - 1].slice(-1);

    if (
      !smallWords.includes(word) ||
      !specialWords.includes(word) ||
      punctuation.includes(lastCharacterPreviousWord),
      i === 0
    ) {
      capitalizeFirstCharacter(words[i]);
    }
  }

  return title;
}

function capitalizeFirstCharacter(word) {
  return word.charAt(0).toUpperCase() + word.slice(1);
}