How it works

Spacetime uses the current epoch, your current offset, and a table of IANA DST-shifts to compute remote times.

The JavaScript Date object models most of the idioms of the Gregorian calendar, and knows the time offset of your current system locale. It can move forward and backwards in your current timezone, but cannot "jump out" of the offset to observe remote times.

Spacetime wraps this functionality by pretending to be in a different offset, but "jumps back" into local time when making calendar-based queries or lookups. This gives the illusion that the date object is subject to a different timezone, with different DST rules.