public/assets/moment-2-13-0/src/lib/units/week-calendar-utils.js

   1 import { daysInYear } from './year';
   2 import { createLocal } from '../create/local';
   3 import { createUTCDate } from '../create/date-from-array';
   4
   5 // start-of-first-week - start-of-year
   6 function firstWeekOffset(year, dow, doy) {
   7     var // first-week day -- which january is always in the first week (4 for iso, 1 for other)
   8         fwd = 7 + dow - doy,
   9         // first-week day local weekday -- which local weekday is fwd
  10         fwdlw = (7 + createUTCDate(year, 0, fwd).getUTCDay() - dow) % 7;
  11
  12     return -fwdlw + fwd - 1;
  13 }
  14
  15 //http://en.wikipedia.org/wiki/ISO_week_date#Calculating_a_date_given_the_year.2C_week_number_and_weekday
  16 export function dayOfYearFromWeeks(year, week, weekday, dow, doy) {
  17     var localWeekday = (7 + weekday - dow) % 7,
  18         weekOffset = firstWeekOffset(year, dow, doy),
  19         dayOfYear = 1 + 7 * (week - 1) + localWeekday + weekOffset,
  20         resYear, resDayOfYear;
  21
  22     if (dayOfYear <= 0) {
  23         resYear = year - 1;
  24         resDayOfYear = daysInYear(resYear) + dayOfYear;
  25     } else if (dayOfYear > daysInYear(year)) {
  26         resYear = year + 1;
  27         resDayOfYear = dayOfYear - daysInYear(year);
  28     } else {
  29         resYear = year;
  30         resDayOfYear = dayOfYear;
  31     }
  32
  33     return {
  34         year: resYear,
  35         dayOfYear: resDayOfYear
  36     };
  37 }
  38
  39 export function weekOfYear(mom, dow, doy) {
  40     var weekOffset = firstWeekOffset(mom.year(), dow, doy),
  41         week = Math.floor((mom.dayOfYear() - weekOffset - 1) / 7) + 1,
  42         resWeek, resYear;
  43
  44     if (week < 1) {
  45         resYear = mom.year() - 1;
  46         resWeek = week + weeksInYear(resYear, dow, doy);
  47     } else if (week > weeksInYear(mom.year(), dow, doy)) {
  48         resWeek = week - weeksInYear(mom.year(), dow, doy);
  49         resYear = mom.year() + 1;
  50     } else {
  51         resYear = mom.year();
  52         resWeek = week;
  53     }
  54
  55     return {
  56         week: resWeek,
  57         year: resYear
  58     };
  59 }
  60
  61 export function weeksInYear(year, dow, doy) {
  62     var weekOffset = firstWeekOffset(year, dow, doy),
  63         weekOffsetNext = firstWeekOffset(year + 1, dow, doy);
  64     return (daysInYear(year) - weekOffset + weekOffsetNext) / 7;
  65 }