how to find capital letters in a string javascript code example

Example 1: javascript check if all capital letter

function isUpper(str) {
    return !/[a-z]/.test(str) && /[A-Z]/.test(str);
}

isUpper("FOO"); //true
isUpper("bar"); //false
isUpper("123"); //false
isUpper("123a"); //false
isUpper("123A"); //true
isUpper("A123"); //true
isUpper(""); //false

Example 2: capitalize first letter of each word javascript

const titleCase = function(text) {
  let newText = '';
  text = text.toLowerCase();
  text = text.charAt(0).toUpperCase() + text.slice(1);
  for (let i = 0; i < text.length; i++) {
    if (text[i] === ' ') {
      newText += ' ' + text[i+1].toUpperCase();
      i++;
    } else {
      newText += text[i];
    }
  }
  return newText;
}