how to convert the first letter in uppercase in javascript code example

Example 1: javascript capitalize words

//capitalize only the first letter of the string. 
function capitalizeFirstLetter(string) {
    return string.charAt(0).toUpperCase() + string.slice(1);
}
//capitalize all words of a string. 
function capitalizeWords(string) {
    return string.replace(/(?:^|\s)\S/g, function(a) { return a.toUpperCase(); });
};

Example 2: js capitalize first letter of each word

function capitalize(str) {
  const arrOfWords = str.split(" ");
  const arrOfWordsCased = [];

  for (let i = 0; i < arrOfWords.length; i++) {
    const word = arrOfWords[i];
    arrOfWordsCased.push(word[0].toUpperCase() + word.slice(1).toLowerCase());
  }

  return arrOfWordsCased.join(" ");
}