how to capitalize string in javascript

//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(); });
};

const lower = 'this is an entirely lowercase string';
const upper = lower.charAt(0).toUpperCase() + lower.substring(1);

const name = 'flavio'
const nameCapitalized = name.charAt(0).toUpperCase() + name.slice(1)

function capitalizeFirstLetter(string) {
  return string.charAt(0).toUpperCase() + string.slice(1);
}

console.log(capitalizeFirstLetter('foo bar bag')); // Foo