I think it leads to side effects because it uses clib's time functions. I have
a pure nim implementation of times, calendars and timezones here:
[https://github.com/treeform/chrono](https://github.com/treeform/chrono)
import chrono
proc test1(unixTime: int64): bool =
var
t = Timestamp(unixTime) # in seconds?
c = t.calendar
c.toStartOf(Day)
echo c.ts
echo c.formatIso
func test(unixTime: int64): bool =
var c = Timestamp(unixTime).calendar # convert to calendar
c.toStartOf(Day) # rewind calendar to start of day
c.ts.float == 0 # convert calendar to timestmap, then to float
discard test1(1233456789)
discard test(1233456789)
Run
But honestly it might be easier to just quantize your thing by a day if you
don't care about timezones and daylight savings.
unixTime - unixTime mod (24*60*60)
Run
