Re: [custom-elements] Invoking lifecycle callbacks before invoking author scripts

On Fri, Feb 26, 2016 at 3:31 PM, Ryosuke Niwa <rniwa@apple.com> wrote:

>
> > On Feb 26, 2016, at 3:22 PM, Elliott Sprehn <esprehn@chromium.org>
> wrote:
> >
> >
> >
> > On Fri, Feb 26, 2016 at 3:09 PM, Ryosuke Niwa <rniwa@apple.com> wrote:
> >>
> >> > On Feb 24, 2016, at 9:06 PM, Elliott Sprehn <esprehn@chromium.org>
> wrote:
> >> >
> >> > Can you give a code example of how this happens?
> >>
> >> For example, execCommand('Delete') would result in sequentially
> deleting nodes as needed.
> >> During this compound operation, unload events may fire on iframes that
> got deleted by this operation.
> >>
> >> I would like components to be notified that they got
> removed/disconnected from the document
> >> before such an event is getting fired.
> >>
> >
> > I'd rather not do that, all the sync script inside editing operations is
> a bug, and you shouldn't depend on the state of the world around you in
> there anyway since all browsers disagree (ex. not all of them fire the
> event sync).
>
> I don't think that's a bug given Safari, Chrome, and Gecko all fires
> unload event before finishing the delete operation.  It's an interoperable
> behavior, which should be spec'ed.
>

Firefox's behavior of when to fire unload definitely doesn't match Chrome
or Safari, but maybe it does in this one instance. I don't think it's worth
trying to get consistency there though, unload is largely a bug, we should
add a new event and get people to stop using it.


>
> Anyway, this was just an easy example I could come up with.  There are
> many other examples that involve DOM mutation events if you'd prefer seeing
> those instead.
>

I'm not interested in making using mutation events easier.


>
> The fact of matter is that we don't live in the future, and it's better
> for API to be consistent in this imperfect world than for it to have weird
> edge cases.  As a matter of fact, if you end up being able to kill those
> sync events in the future, this will become non-issue since
> end-of-nano-task as you (Google) proposed will happen before dispatching of
> any event.
>
> As things stand, however, we should dispatch lifecycle callbacks before
> dispatching these (legacy but compat mandating) events.
>

I disagree. Mutation events are poorly speced and not interoperably
implemented across browsers. I don't think we should run nanotasks down
there.

- E