Hackerrank Challenge day-of-the-programmer : https://www.hackerrank.com/challenges/day-of-the-programmer/problem?isFullScreen=true

dayOfProgrammer.js

function dayOfProgrammer(year) {
    // Write your code here
    let feb = 0;
    let initialDaySum = 0;
    
    if (year >= 1700 && year <= 1917) {
        if (year % 4 === 0) feb = 29;
        else feb = 28;
    } 
    else if (year > 1918 && year <= 2700) {
        if (year % 400 === 0 || (year % 4 === 0 && year % 100 !== 0)) feb = 29;
        else feb = 28;
    } else {
        feb = 29 - 14;
    }
    initialDaySum = 31 + feb + 31 + 30 + 31 + 30 + 31 + 31;
    let date = 256 - initialDaySum;
    return `${date+'.' + '09' + '.' + year}`;
}