make letter of first word capital javascript code example

Example 1: javascript capitalize first letter

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

Example 2: javascript first letter uppercase

const upperCase = function(names){
    const toLower = names.toLowerCase().split(' ');
    const namesUpper = [];
    for(const wordName of toLower){
        namesUpper.push(wordName[0].toUpperCase() + wordName.slice(1));
    }
    return namesUpper.join(' ');
}