Get friday from week number and year in javascript

Question

I have week number and year, need to find out date (friday) in that week and year.

function getFriday(week_num, year)
{
    ?

    return friday_date_object;         


        

Answer 1

Here's some quick code

var DAY = 86400000;

function getFriday(weekNum, year) {
  var year = new Date(year.toString()); // toString first so it parses correctly year numbers
  var daysToFriday = (5 - year.getDay()); // Note that this can be also negative
  var fridayOfFirstWeek = new Date(year.getTime() + daysToFriday * DAY);
  var nthFriday = new Date(fridayOfFirstWeek.getTime() + (7 * (weekNum - 1) * DAY));
  return nthFriday;
}

Split some variables for readability.

But if you find yourself writing more complex time operations, you're better using a library instead.