Query

Is Before

Check if a date is before another date.

  1. // Moment.js
  2. moment('2010-10-20').isBefore('2010-10-21');
  3. // => true
  5. // Native
  6. new Date(2010, 10, 20) < new Date(2010, 10, 21);
  7. // => true
  9. // date-fns
  10. import isBefore from 'date-fns/isBefore';
  11. isBefore(new Date(2010, 9, 20), new Date(2010, 9, 21));
  12. // => true
  14. // dayjs
  15. dayjs('2010-10-20').isBefore('2010-10-21');
  16. // => true
  18. // luxon
  19. DateTime.fromISO('2010-10-20') < DateTime.fromISO('2010-10-21');
  20. // => true

Is Same

Check if a date is the same as another date.

  1. // Moment.js
  2. moment('2010-10-20').isSame('2010-10-21');
  3. // => false
  4. moment('2010-10-20').isSame('2010-10-20');
  5. // => true
  6. moment('2010-10-20').isSame('2010-10-21', 'month');
  7. // => true
  9. // Native
  10. new Date(2010, 9, 20).valueOf() === new Date(2010, 9, 21).valueOf();
  11. // => false
  12. new Date(2010, 9, 20).valueOf() === new Date(2010, 9, 20).valueOf();
  13. // => true
  14. new Date(2010, 9, 20).getTime() === new Date(2010, 9, 20).getTime();
  15. // => true
  16. new Date(2010, 9, 20).valueOf() === new Date(2010, 9, 20).getTime();
  17. // => true
  18. new Date(2010, 9, 20).toDateString().substring(4, 7) ===
  19.   new Date(2010, 9, 21).toDateString().substring(4, 7);
  20. // => true
  22. // date-fns
  23. import isSameDay from 'date-fns/isSameDay';
  24. import isSameMonth from 'date-fns/isSameMonth';
  25. isSameDay(new Date(2010, 9, 20), new Date(2010, 9, 21));
  26. // => false
  27. isSameDay(new Date(2010, 9, 20), new Date(2010, 9, 20));
  28. // => true
  29. isSameMonth(new Date(2010, 9, 20), new Date(2010, 9, 21));
  30. // => true
  32. // dayjs
  33. dayjs('2010-10-20').isSame('2010-10-21');
  34. // => false
  35. dayjs('2010-10-20').isSame('2010-10-20');
  36. // => true
  37. dayjs('2010-10-20').isSame('2010-10-21', 'month');
  38. // => true
  40. // luxon
  41. (+DateTime.fromISO('2010-10-20') ===
  42.   +DateTime.fromISO('2010-10-21') +
  43.     // => false
  44.     DateTime.fromISO('2010-10-20')) ===
  45.   +DateTime.fromISO('2010-10-20');
  46. // => true
  47. DateTime.fromISO('2010-10-20').hasSame(DateTime.fromISO('2010-10-21'), 'month');
  48. // => true

Is After

Check if a date is after another date.

  1. // Moment.js
  2. moment('2010-10-20').isAfter('2010-10-19');
  3. // => true
  5. // Native
  6. new Date(2010, 9, 20) > new Date(2010, 9, 19);
  7. // => true
  9. // date-fns
  10. import isAfter from 'date-fns/isAfter';
  11. isAfter(new Date(2010, 9, 20), new Date(2010, 9, 19));
  12. // => true
  14. // dayjs
  15. dayjs('2010-10-20').isAfter('2010-10-19');
  16. // => true
  18. // luxon
  19. DateTime.fromISO('2010-10-20') > DateTime.fromISO('2010-10-19');
  20. // => true

Is Between

Check if a date is between two other dates.

  1. // Moment.js
  2. moment('2010-10-20').isBetween('2010-10-19', '2010-10-25');
  3. // => true
  5. // date-fns
  6. import isWithinInterval from 'date-fns/isWithinInterval';
  7. isWithinInterval(new Date(2010, 9, 20), {
  8.   start: new Date(2010, 9, 19),
  9.   end: new Date(2010, 9, 25),
  10. });
  11. // => true
  13. // dayjs ⚠️ requires isBetween plugin
  14. import isBetween from 'dayjs/plugin/isBetween';
  15. dayjs.extend(isBetween);
  16. dayjs('2010-10-20').isBetween('2010-10-19', '2010-10-25');
  17. // => true
  19. // luxon
  20. Interval.fromDateTimes(
  21.   DateTime.fromISO('2010-10-19'),
  22.   DateTime.fromISO('2010-10-25')
  23. ).contains(DateTime.fromISO('2010-10-20'));
  24. // => true

Is Leap Year

Check if a year is a leap year.

  1. // Moment.js
  2. moment([2000]).isLeapYear();
  3. // => true
  5. // Native
  6. new Date(2000, 1, 29).getDate() === 29;
  7. // => true
  9. // date-fns
  10. import isLeapYear from 'date-fns/isLeapYear';
  11. isLeapYear(new Date(2000, 0, 1));
  12. // => true
  14. // dayjs ⚠️ requires isLeapYear plugin
  15. import isLeapYear from 'dayjs/plugin/isLeapYear';
  16. dayjs.extend(isLeapYear);
  17. dayjs('2000-01-01').isLeapYear();
  18. // => true
  20. // luxon
  21. expect(DateTime.local(2000).isInLeapYear).toBeTruthy();
  22. // => true

Is a Date

Check if a variable is a native js Date object.

  1. // Moment.js
  2. moment.isDate(new Date());
  3. // => true
  5. // Native
  6. new Date() instanceof Date;
  7. // => true
  9. // date-fns
  10. import isDate from 'date-fns/isDate';
  11. isDate(new Date());
  12. // => true
  14. // dayjs 
  15. dayjs(new Date()).isValid()
  17. // luxon
  18. DateTime.local().isValid;
  19. // => true