Get full date from day of the year

Question

I'm using js and jquery. I've been looking on the page and I found this: Javascript calculate the day of the year (1 - 366) I'm trying to do the oposite.

For example:

208 would be today (2016/07/26)

Any idea how could i do this?

Thank you very much in advance.

score 8 · Answer 1 · answered Jul 26 '16 at 11:56

8

Try this:

function dateFromDay(year, day){
  var date = new Date(year, 0); // initialize a date in `year-01-01`
  return new Date(date.setDate(day)); // add the number of days
}

dateFromDay(2016, 208);

answered Jul 26 '16 at 11:56

Jayesh Chitroda

4,987
13
18

score 6 · Accepted Answer · answered Jul 26 '16 at 12:06

6

The shortest way:

new Date(2016, 0, 208)

will return Date 2016-07-26

answered Jul 26 '16 at 12:06

Yan Pak

1,767
2
19
15

Easier than I expected. Thank you very much – Hector Landete Jul 26 '16 at 12:10

score -1 · Answer 3 · answered Jul 26 '16 at 12:10

function dayNumToDate(numDays) {
  var thisYear = new Date().getFullYear();
  var initDate = new Date("JANUARY, 1," +  thisYear);
  var millis = numDays * 24 * 60 *60 * 10000; 
  var newDate = new Date(millis + initDate.getTime());
  return newDate;
}
var date = dayNumToDate(208);
alert(date.toString());

score -1 · Answer 4 · answered Jul 26 '16 at 12:26

//To initialize date function

var now = new Date();

// the number of day to convert in Date

var curr_day_number = 208;

//Calculate total time of a single day

var oneDay = 1000 * 60 * 60 * 24;

//Calculate total time all days so

var total_number_of_time_of_day = curr_day_number * oneDay;

//calcuclate start day of the year

var start_date_of_year = new Date(now.getFullYear(), 0, 0);

//calculate start date of year time stamp

var start_date_of_year_timestamp = new Date(start_date_of_year).getTime();

//calulate total time stamp start of the year with total days of the year

var calculated_timestamp = start_date_of_year_timestamp + total_number_of_time_of_day;

// convert time stamp into Date using Date function

var calculated_date = new Date(calculated_timestamp);

document.write(calculated_date);

This will help you out in detail.

There is solution with only one line. It complies with the specification, is concise and easily readable. So why would anyone want to use a solution that spans several lines, makes potentially error-prone calculations, and is hard to read and understand? — str, Jul 26 '16 at 12:50

Get full date from day of the year

4 Answers4