Convert string to sentence case in javascript

Question

I want a string entered should be converted to sentence case in whatever case it is.

Like

hi all, this is derp. thank you all to answer my qu

Answer 1

On each line this script will print ..... Sunday Monday Tuesday Wednesday Thursday Friday Saturday.

let rg = /(^\w{1}|\.\s*\w{1})/gi;

const days = ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'];

for(let day of days) {
    console.log(day.replace(rg, function(toReplace) {
    return toReplace.toUpperCase();
}))