Automatic performance testing

[j-f1]

I’ve seen repositories before that have a bot post a comment on all new PRs with a comparison of the perf tests between main and the PR branch. This would be very nice to have so we don’t accidentally introduce regressions, and to celebrate perf improvements when they’re added.

[j-f1]

Here’s an action that could probably be adapted to measure perf instead of bundle size: https://github.com/preactjs/compressed-size-action/blob/master/src/index.js

[MaxDesiatov]

Can this be considered resolved now?