CustomElement Reactions#2394
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While this PR touches a lot of files, and isn't trivial, many of the changes
are either:
1 - removing guards added in previous PRs, e.g.
#1969
#2172
#2313
#2366
2 - Adding the `.ce_reactions = true` flag to various WebAPIs
CustomElements have callbacks, e.g. connectedCallback. Also, many WebAPI calls
are implemented as a series of mutations, e.g. appendChild = remove from current
+ append to new.
These two things interact in an important way: when should callbacks execute?
Before this PR, we were invoking callbacks at each individual step. This is
(a) technically wrong and (b) breaks a lot of assumptions (the reason the above
4 PRs were needed to fix bugs).
This PR adds a `_ce_reactions` queue to the frame. And, instead of invoking
callbacks, we "enqueue" the reaction. At various boundaries, a scope is created
the DOM manipulation is done, and then we pop the scope, invoking all queued
reactions.
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While this PR touches a lot of files, and isn't trivial, many of the changes are either:
1 - removing guards added in previous PRs, e.g.
#1969
#2172
#2313
#2366
2 - Adding the
.ce_reactions = trueflag to various WebAPIsCustomElements have callbacks, e.g. connectedCallback. Also, many WebAPI calls are implemented as a series of mutations, e.g. appendChild = remove from current & append to new.
These two things interact in an important way: when should callbacks execute? Before this PR, we were invoking callbacks at each individual step. This is (a) technically wrong and (b) breaks a lot of assumptions (the reason the above 4 PRs were needed to fix bugs).
This PR adds a
_ce_reactionsqueue to the frame. And, instead of invoking callbacks, we "enqueue" the reaction. At various boundaries, a scope is created the DOM manipulation is done (which queues reactions instead of invoking them directly), and then we pop the scope, invoking all queued reactions.