Feature request: Allow emitting preloads for page data and chunks

[iamakulov]

Background

In #35408, Gatsby made a decision to remove <link rel="preload">s for page data and JS chunks. That change was made to improve LCP.

Unfortunately, the consequence of that change is that now, JS loads in a three-step waterfall:

(Step 1: the Gatsby bundle. Step 2: the page data. Step 3: the page chunks.)

Only after all three roundtrips complete, the page becomes interactive, and stuff like hamburger menus starts working.

Request

I’m a web performance engineer. A client of mine has a site with interactive elements where the later hydration happens, the longer the site stays non-functional. This worsens the UX more than it’s improved by the slight LCP win.

Bringing back preloading would remove the waterfall and solve this issue.

Would Gatsby consider bringing back preloading? I understand not every site has to be interactive ASAP – most sites are static. So I’m happy if this is brought as a flag (or even as an appropriate plugin API).