Renames JsContext -> js.Context, JsObject -> js.Object and JsThis -> js.This
which is more consistent with the other types. The JsObject -> js.Object is
the reason so many files were touched.
This is still a [messy] transition, with more refactoring planned to clean it
up.
scroll alias for scrollTo
add get_scrollX and get_scrollY, along with their aliases: pageXOffset and
pageYOffset. These always return 0, unless scroll or scrollTo are called.
There's always going to be ambiguity between a string and a Uint8Array. We
already had TypedArray(u8) as a discriminator when _returning_ values. But now
the type is also used by mapping JS values to Zig. To support this efficiently
when probing the union, the typed array mapping logic was extracted into its
own function (so that it can be used by the probe).
This solves two issues. First, it's more correct, the indexers should be live.
Second, it makes sure that anything with an HTMLCollection prototype, like
HTMLOptionsCollection, also gets access to the index getters.
We could solve the 2nd issue by making `postAttach` work up the prototype
chain, but since postAttach is wrong (not live), I prefer this solution.
Allows dynamic imports to be loading asynchronously. I know reddit isnt the
best example, since it doesn't fully load, but this reduced the load time from
~7.2s to ~4.8s.
The first time a `slotchange` event is registered, we setup a SlotChangeMonitor
on the page. This uses a global (ugh) MutationEvent to detect slot changes.
We could improve the perfomance of this by installing a MutationEvent per
custom element, but a global is obviously a lot easier.
Our MutationEvent currently fired _during_ the changes. This is problematic
(in general, but specifically for slotchange). You can image something like:
```
slot.addEventListener('slotchange', () => {
// do something with slot.assignedNodes()
});
```
But, if we dispatch the `slotchange` during the MutationEvent, assignedNodes
will return old nodes. So, our SlotChangeMonitor uses the page scheduler to
schedule dispatches on the next tick.
Refactors some of the module loading logic. Both normal modules import and
dynamic module import now share more of the same code - they both go through
the slightly modified `module` function.
Dynamic modules now check the cache first, before loading, and when cached,
resolve the correct promise. This can now happen regardless of the module
loading state.
Also tried to replace some page arenas with call arenas and added some basic
tests for both normal and dynamic module loading.
If a webapi has a []const u8 parameter, then the page.call_arena is used. This
is our favorite arena to use, but if the string value has a lifetime beyond the
call, it then needs to be duped again (using page.arena).
When a webapi has a Env.String parameter, the page.arena will be used directly
to get the value from V8, removing the need for an intermediary dupe in the
call_arena.
This allows HTMLCollections to be streamlined. They no longer need to dupe the
filter (tag name, class name, ...), which means they can no longer fail. It also
means that we no longer need to needlessly dupe the string literals.
