Spot the bug - #99: Text Preview Box

This title-case formatter mangles every other word somehow.

function toTitleCase(sentence) {
  const words = sentence.split(' ');
  const result = [];

  for (let i = 0; i < words.length; i++) {
    const word = words[i];
    const firstLetter = word.charAt(0).toUpperCase();
    const rest = word.slice(1).toLowerCase();
    result.push(firstLetter + rest);
  }

  return result.join(' ');
}

const headlines = [
  'the quick brown fox',
  'ATTACK OF THE KILLER TOMATOES',
  'a tale of two cities'
];

headlines.forEach(h => {
  console.log(toTitleCase(h));
});

const nameTag = document.getElementById('preview');
nameTag.textContent = toTitleCase('welcome new employee');

Reply with what is broken and how you would fix it.