how to change the casing of a string in javascript code example

Example: string to title case javascript

function titleCase(sentence) {
  let sentence = string.toLowerCase().split(" ");
  for (let i = 0; i < sentence.length; i++) {
    sentence[i] = sentence[i][0].toUpperCase() + sentence[i].slice(1);
  }
  
  return sentence.join(" ");
}