change one letter to uppercase js code example

Example 1: javascript capitalize

myString = 'the quick green alligator...';
myString.replace(/^\w/, (c) => c.toUpperCase());

myString = '    the quick green alligator...';
myString.trim().replace(/^\w/, (c) => c.toUpperCase());

Example 2: captitalize js

function capitalize2(str) {
  str = str.toLowerCase();

  const arrOfWords = str.split(" ");

  const arrOfWordsCased = [];

  for (let i = 0; i < arrOfWords.length; i++) {
    const char = arrOfWords[i].split("");
    char[0] = char[0].toUpperCase();

    res.push(char.join(""));
  }
  return arrOfWordsCased.join(" ");
}