how to change the first letter of a word to uppercase in javascript code example

Example 1: capitalise first letter js

const string = "tHIS STRING'S CAPITALISATION WILL BE FIXED."
const string = string.charAt(0).toUpperCase() + string.slice(1)

Example 2: js capitalize first letter of each word

const titleCase = title => title
    .split(/ /g).map(word =>
        `${word.substring(0,1).toUpperCase()}${word.substring(1)}`)
    .join(" ");