RFC: Drop local-time concern, relative-time is whats interesting

[josh]

We really don't even use the regular date localization in github itself. It was probably premature to even try to extract it.

Maybe we can rename and focus this library on <relative-time>.

what do you guys think?

/cc @mislav @eanakashima @dgraham

[dgraham]

To summarize the conversation @josh and I had in chat:

• Not much code can be deleted if we remove local-time. The sizable amount of strftime code, in particular, needs to stay regardless, because it's used in relative date formats older than two days (e.g. on May 6, yesterday at 11:45am).
• Separating the behavior into two elements–local-time and relative-time–makes sense because relative-time needs a periodic JavaScript timer function running, while local-time doesn't. It also removes the magic relative keyword value in <local-time format="relative">. The format attribute is then strictly for strftime formatting strings.

So without much code size savings, the question is whether we need local-time at all. We used it in only one place on the site, which @josh recently converted back into static Ruby rendering in UTC time. I'd like to keep local-time, though. We're almost getting it for free since most of the JavaScript is related to formatting and updating relative times.

[dgraham]

One other approach we could take is to subclass the standard <time> element with the web component is attribute. So a standard <time datetime="2014-05-08T14:35:00-06:00"></time> element becomes:

• <time is="local" format="%l:%M%P" datetime="2014-05-08T14:35:00-06:00"></time>
• <time is="relative" datetime="2014-05-08T14:35:00-06:00"></time>

@josh Any reason you originally opted for a new custom element rather than subclassing time?

[josh]

I actually kinda like dig that idea.

I'd say I didn't originally subclass because <time> itself offers nothing interesting over the basic HTMLElement.

Its a bummer, but even is requires a - prefix in the name. So its going to have to be

<time is="local-time">
<time is="relative-time">

I really like this, lets do it!

[eanakashima]

👍 ✨ Really like the look of <time is="local-time"> and <time is="relative-time">.