Transition tests fail with latest jsdom

[Conduitry]

Couple of things going on here. When Rich cuts new builds, he (presumably) uses the dependencies as installed by Yarn, whereas CI uses npm and gets the latest versions of all dependencies. If the releases use Yarn, probably the CI jobs should too. There should probably also be an effort to update deps regularly, since they get bundled.

The other issue here is that, with the latest version of jsdom (upgrade from 11.5.1 to 11.6.0), tests related to transitions fail. I believe this is partially/largely because of the change "Added a window.performance implementation, including the basics of the High Resolution Time specification: performance.now(), performance.timeOrigin, and performance.toJSON()." Indeed, if the hack in the tests is changed from window.performance = { now: () => raf.time }; to window.performance.now = () => raf.time;, all but one of the tests pass (under the latest jsdom), although I'm not sure what this means.

[Conduitry]

The one final test failure looks to be fixed by updating to the just-releast jsdom 11.6.1 (in addition to making the above window.performance.now change).

[Zirro]

Note that recent versions of jsdom include a requestAnimationFrame()-implementation when you enable the pretendToBeVisual option. If you don't need to use it in a way that's different from browsers, you might not have to shim it or modify window.performance.now() any more.

[Rich-Harris]

closing. thank you!