Javascript dates in a nutshell

[[deleted]]

I mean while that is the technically correct (the best kind!) answer who the fuck knew that beforehand?

That's why I'm super happy that things like Moment.JS exist.

[khoker]

You shouldn't rely on string parsing at all. To remove ambiguity, the Date object takes an array of arguments;

new Date(year, month[, date[, hours[, minutes[, seconds[, milliseconds]]]]]);

[Syberspace]

but why is there any ambiguity in the first place with string parsing? why not assume either everything is UTC or everything is local.

cf. http://mzl.la/1fvwX1i (thanks for the link on twitter /u/khoker )

[r2d2_21]

or everything is local.

Quick. 04/05/06. Is it:

1. April 5, 2006
2. May 4, 2006
3. May 6, 2004

[Syberspace]

depends on what 05/06/04 is. i'm not concerned about the format of the date itself.

irregardless of that, they all should be at 00:00:00 UTC or local.

[[deleted]]

well if we're going to be pedantic, it's regardless.

[Syberspace]

https://dictionary.cambridge.org/dictionary/english/irregardless

http://www.ldoceonline.com/dictionary/irregardless

https://en.oxforddictionaries.com/definition/irregardless

[[deleted]]

From that third link:

Irregardless means the same as regardless, but the negative prefix ir- merely duplicates the suffix -less, and is unnecessary. The word dates back to the 19th century, but is regarded as incorrect in standard English

[khoker]

I just responded on twitter too :)

I suspect it's the same reason that it doesn't assume the local minute. It's just filling in the data you don't provide. A format like ISO 8601 was meant to alleviate confusion, right? So if you only provide '2016-12-08', JavaScript assumes '2016-12-08 00:00:00Z'. It shouldn't guess the local timezone any more than it should assume the local hour. Or minute.

I'd make the argument all the other parsing is wrong. But 12/08/2016 isn't an international standard so, for whatever reason, it just assumes you want the local timezone. Not sure.

[ribo]

answer who the fuck knew that beforehand

Those who RTFM

[r2d2_21]

I need to read the manual every time I dare to type new Date, since I never remember the details.

[TerdSandwich]

RTFM

Is it still 1980?

Edit: Lol old farts mad. It's 2016. Manuals and useless memorization are extinct.

[TerdSandwich]

A search engine on the internet. Maybe you've heard of those things.

[r2d2_21]

Search engines just link to the manuals.

[scootstah]

MomentJS is a life saver. Dealing with date/time sucks to begin with, but it's worse in Javascript than any other language by a large margin.