how to convert first letter of string into capital in javascript code example

Example 1: first letter tuUppercase

const string = "tHIS STRING'S CAPITALISATION WILL BE FIXED."
const string = string[0].toUpperCase() + string.slice(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(' ');
}