Sort preload assets so that styles are first #576
Merged
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
When getting the preload assets, sort them so that the style assets are first.
I saw a PR over in next.js (vercel/next.js#9486). Apparently preloading the JS first can slow down some browsers and delay the styles loading and therefore negatively impact performance/lighthouse scores.
I tested the approach on our own site and it led to quite a dramatic improvement in lighthouse score.
Test plan
I tried to run the tests locally but it errored with something I didn't understand. I'm afraid I don't have the time at the moment to wrap my head around it but figured this PR may be useful to some people so would submit it anyway.