CodeSignal - Proper Noun Correction

properNounCorrection.js

/*
Proper nouns always begin with a capital letter, followed by small letters.

Correct a given proper noun so that it fits this statement.

Example

For noun = "pARiS", the output should be
properNounCorrection(noun) = "Paris";
For noun = "John", the output should be
properNounCorrection(noun) = "John".
*/

function properNounCorrection(noun) {
    // Turns the whole word lowercase, pARIS becomes paris
    let lowerCaseNoun = noun.toLowerCase();
    // Turns the first letter uppercase, p becomes P
    let capitalizedFirstLetter = lowerCaseNoun.charAt(0).toUpperCase();
    // Turns paris into aris
    let removeFirstLetter = lowerCaseNoun.substr(1);
    // Concats P with aris to get Paris
    return capitalizedFirstLetter + removeFirstLetter;
}