How to display the day of the week and month given the ordinal number of the day of the year?

Question

JavaScript

Let's say I write 34 and outputs - February 3 day of the week Sun .....
With the help of if else it turns out but the whole lecture)) In theory, it is necessary to do it in cycles, but how?

Answer 1

function dateFromDay(year, day){
  const date = new Date(year, 0);
  return new Date(date.setDate(day));
}

dateFromDay(2019, 34); // Sun Feb 03 2019 00:00:00 GMT+0300 (Москва, стандартное время)

Answer 2

https://learn.javascript.ru/datetime Read first about JS date and time to understand what's going on. These are not libraries) Everything has already been done extremely simply, no conditions are needed