index.js 2.4 KB

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  1. import toDate from "../toDate/index.js";
  2. import requiredArgs from "../_lib/requiredArgs/index.js";
  3. var MILLISECONDS_IN_DAY = 24 * 60 * 60 * 1000;
  4. /**
  5. * @name getOverlappingDaysInIntervals
  6. * @category Interval Helpers
  7. * @summary Get the number of days that overlap in two time intervals
  8. *
  9. * @description
  10. * Get the number of days that overlap in two time intervals
  11. *
  12. * @param {Interval} intervalLeft - the first interval to compare. See [Interval]{@link docs/Interval}
  13. * @param {Interval} intervalRight - the second interval to compare. See [Interval]{@link docs/Interval}
  14. * @returns {Number} the number of days that overlap in two time intervals
  15. * @throws {TypeError} 2 arguments required
  16. * @throws {RangeError} The start of an interval cannot be after its end
  17. * @throws {RangeError} Date in interval cannot be `Invalid Date`
  18. *
  19. * @example
  20. * // For overlapping time intervals adds 1 for each started overlapping day:
  21. * getOverlappingDaysInIntervals(
  22. * { start: new Date(2014, 0, 10), end: new Date(2014, 0, 20) },
  23. * { start: new Date(2014, 0, 17), end: new Date(2014, 0, 21) }
  24. * )
  25. * //=> 3
  26. *
  27. * @example
  28. * // For non-overlapping time intervals returns 0:
  29. * getOverlappingDaysInIntervals(
  30. * { start: new Date(2014, 0, 10), end: new Date(2014, 0, 20) },
  31. * { start: new Date(2014, 0, 21), end: new Date(2014, 0, 22) }
  32. * )
  33. * //=> 0
  34. */
  35. export default function getOverlappingDaysInIntervals(dirtyIntervalLeft, dirtyIntervalRight) {
  36. requiredArgs(2, arguments);
  37. var intervalLeft = dirtyIntervalLeft || {};
  38. var intervalRight = dirtyIntervalRight || {};
  39. var leftStartTime = toDate(intervalLeft.start).getTime();
  40. var leftEndTime = toDate(intervalLeft.end).getTime();
  41. var rightStartTime = toDate(intervalRight.start).getTime();
  42. var rightEndTime = toDate(intervalRight.end).getTime();
  43. // Throw an exception if start date is after end date or if any date is `Invalid Date`
  44. if (!(leftStartTime <= leftEndTime && rightStartTime <= rightEndTime)) {
  45. throw new RangeError('Invalid interval');
  46. }
  47. var isOverlapping = leftStartTime < rightEndTime && rightStartTime < leftEndTime;
  48. if (!isOverlapping) {
  49. return 0;
  50. }
  51. var overlapStartDate = rightStartTime < leftStartTime ? leftStartTime : rightStartTime;
  52. var overlapEndDate = rightEndTime > leftEndTime ? leftEndTime : rightEndTime;
  53. var differenceInMs = overlapEndDate - overlapStartDate;
  54. return Math.ceil(differenceInMs / MILLISECONDS_IN_DAY);
  55. }