Google complaining about slow Interaction to Next Paint (INP) on Discourse sites

[david (David Taylor)]

@merefield

Can you remind me what the high level technical change of approach here that facilitates that improvement?

The improvement to the INP?

With the old spinner, the sequence was

1. Click link
2. Ember tears down all DOM and cleans up components from the old route
3. Spinner rendered to screen
4. Once network request resolved, render new route to DOM

With the slider, we skip step 2. The slider gets rendered immediately, without needing to wait for the expensive teardown process.

@david

improving INP is one of the motivations for switching Discourse’s page navigation animation from a full-page ‘spinner’ to a slider

I should clarify here: the main motivation for us switching the default is the improved UX. The INP metric improvement is also nice, but not the primary reason for the change.