34 lines
1.2 KiB
JavaScript
34 lines
1.2 KiB
JavaScript
|
import toDate from "../toDate/index.js";
|
||
|
|
import startOfISOWeek from "../startOfISOWeek/index.js";
|
||
|
|
import startOfISOWeekYear from "../startOfISOWeekYear/index.js";
|
||
|
|
import requiredArgs from "../_lib/requiredArgs/index.js";
|
||
|
|
var MILLISECONDS_IN_WEEK = 604800000;
|
||
|
|
/**
|
||
|
|
* @name getISOWeek
|
||
|
|
* @category ISO Week Helpers
|
||
|
|
* @summary Get the ISO week of the given date.
|
||
|
|
*
|
||
|
|
* @description
|
||
|
|
* Get the ISO week of the given date.
|
||
|
|
*
|
||
|
|
* ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
|
||
|
|
*
|
||
|
|
* @param {Date|Number} date - the given date
|
||
|
|
* @returns {Number} the ISO week
|
||
|
|
* @throws {TypeError} 1 argument required
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* // Which week of the ISO-week numbering year is 2 January 2005?
|
||
|
|
* const result = getISOWeek(new Date(2005, 0, 2))
|
||
|
|
* //=> 53
|
||
|
|
*/
|
||
|
|
|
||
|
|
export default function getISOWeek(dirtyDate) {
|
||
|
|
requiredArgs(1, arguments);
|
||
|
|
var date = toDate(dirtyDate);
|
||
|
|
var diff = startOfISOWeek(date).getTime() - startOfISOWeekYear(date).getTime(); // Round the number of days to the nearest integer
|
||
|
|
// because the number of milliseconds in a week is not constant
|
||
|
|
// (e.g. it's different in the week of the daylight saving time clock shift)
|
||
|
|
|
||
|
|
return Math.round(diff / MILLISECONDS_IN_WEEK) + 1;
|
||
|
|
}
|