| add | adds the number of date units to a date |
| copy | creates a copy of a date |
| datePart | gets the date part of a date object |
| dateToStr | creates a new date formatting method |
| dayStart | gets the start of a day |
| equal | compares two dates |
| getISOWeek | gets the number of the week by ISO (local time zone) |
| getUTCISOWeek | gets the number of the week by ISO (UTC time) |
| isHoliday | returns true if date is a holiday |
| monthStart | gets the start of the month |
| strToDate | creates a new date parsing method |
| timePart | gets the time part of a date in seconds |
| toFixed | adds a leading zero to a number, if it's less than 10 |
| weekStart | gets the start of the week |
| yearStart | gets the start of the year |