[lit-html] styleMap fails when update contains priority directive

[regevbr]

fix: #3767

Added test to verify that issue existed before, and fixed.

The fix is simple - remove the !important directive if exists, and set the priority argument in the call to setProperty

[changeset-bot]

🦋 Changeset detected

Latest commit: 2743734

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
lit-html	Patch
lit	Patch

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[justinfagnani]

Thanks for the fix!

[regevbr]

@justinfagnani not sure why, but some CI are failing with strange github errors. Have you seen that before?

https://github.com/lit/lit/actions/runs/4544819440
https://github.com/lit/lit/actions/runs/4544819448

[justinfagnani]

Thanks!

[dlockhart]

FYI, this change broke some stuff for us that was arguably incorrect but was working before nonetheless. The situation we had was something like this:

styleMap({
  'color': 'red',
  'aspect-ratio': 2.1
});

Obviously that Number should be a String, but this code was working but with this change it blows up on the .endsWith() call. Suggest maybe doing a type check or using an optional chain?