abstract-over DST change in .diff() about spacetime HOT 4 CLOSED

hey, thanks for your help.
Yeah, in my opinion, .add(1, 'week') should compensate for the dst change, and move a full 7 days. That seems to be working right now.

it looks like the confusion is in the .diff() results then.
We may want to add this 'dst compensate' stuff to .diff.

hmmm. Do you agree?

(ps you don't need to use .clone() anymore for that)

from spacetime.

Hi, @spencermountain, thanks for merge my changes, I'm really happy to help here.

Just want to be clear that current implementation is what your described, it works like this

> spacetime('2018-03-29T00:00:00.000+13:00').add(1, 'week').format('iso')
2018-04-04T23:00:00.000+12:00

Not exactly 'full 7 days' literally but 7 days worth of ms.

I'm totally agree the idea of dst awareness diff, just haven't figure out what's the more proper way to interprete the results, eg:

start = '2018-03-29T00:00:00.000+13:00'

• Options 1, loyally repensents the ms
  diff('2018-04-04T23:00:00.000+12:00', start) output 7 days
  diff('2018-04-05T00:00:00.000+12:00', start) output 7 days 1 hour

• Options 2, compensate to dst, but might be weird looking
  diff('2018-04-04T23:00:00.000+12:00', start) outputs 6 days 24 hours (because dst crossing on 01/Apr makes that day 25 hours long. it might end up been xxxxx days xxx hours for long distant dates crossing dst multiple times)
  diff('2018-04-05T00:00:00.000+12:00', start) outputs 7 days

any suggestions?

from spacetime.

oh hey, you're completely right. Thank you. I was wrong yesterday.
yeah, adding a week to thursday at 4pm should always return a result at thursday at 4pm.

the add function is not correct then. The diff calculation can just use the same methods, so will not require any additional dst awareness step.

Sorry about this. I can take a look at this, this week - or I will happily merge a PR with however you decide to fix it.
thanks!

from spacetime.

hi, @spencermountain the PR has been filed, now add function does exactly what we discussed for 'year/season/quarter/month/week/days', but not for 'hour/minutes/sec' since that's some exact number user ask to add.

Please let me know your thoughts, Thanks!

from spacetime.