JSFiddle - React, Tailwind, and code Playground

by brigand

JavaScript

function jday(date) {
  const firstDay = new Date(0);
  firstDay.setUTCFullYear(date.getUTCFullYear());
  const day = `${Math.floor((date - firstDay) / (24 * 60 * 60 * 1000))}`;
  console.log(day)
  return day.padStart(3, '0');
}
jday(new Date())
jday(new Date('2018-07-08'))