Fix HTML caching in service worker

[theg1239]

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[vercel]

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Project	Deployment	Actions	Updated (UTC)
examcooker-dev	Error		Jun 18, 2026 12:38am

[greptile-apps]

Greptile Summary

• Updates the service worker cache version and cache policy for HTML responses.
• Handles HTML navigations through the network while preserving the offline fallback path.
• Prevents native route prefetches from writing uncacheable page routes into the page cache.
• Adds a standalone service worker cache-policy regression test script.

Confidence Score: 3/5

The service worker caching direction is sound, but the cache-policy guard is not part of the normal validation path and the prefetch loop changes request pacing.

The changed surface is small and focused, with a targeted standalone regression check, but the remaining issues can allow regressions to pass unnoticed and can alter runtime prefetch behavior.

scripts/test-service-worker-cache-policy.mjs and public/sw.js

T-Rex Logs

What T-Rex did

• Reproduced the CI build path and confirmed the normal npm build validation omits the service worker cache policy script; the standalone test script runs and passes when invoked directly.
• Ran the service worker prefetch pacing harness against the public/sw.js and observed that the /mod route was skipped as uncacheable and /notes arrived earlier than the 240ms pacing (120ms after /).
• Compared the HTML fetch handler behavior before and after changes; the before path used staleWhileRevalidate and cached one item, while the after path uses networkOnlyWithOfflineFallback and cached nothing.
• Compared offline fallback behavior; the after path returned 200 OK with the offline fallback body and did not cache the failed HTML, unlike the before path.
• Reviewed prefetch no-persist sequences; the before artifact showed caches opened and cache puts for "/" and "/notes", while the after artifact showed zero caches.open and zero cache.put calls.

_{Ran code and verified through T-Rex}

Comments Outside Diff (1)

1. public/sw.js, line 105-111 (link)

   Keep prefetch pacing

   This continue skips the existing await wait(120) throttle for uncacheable routes. The current native prefetch list includes /mod in the skipped set, so /notes can be fetched immediately after / instead of preserving the per-route pacing. When more skipped routes are present, the service worker can burst the remaining prefetches instead of spacing them out.

   Artifacts

   
   

   Repro: service worker prefetch pacing harness

   • Contains supporting evidence from the run (text/javascript; charset=utf-8).

   Repro: prefetch trace output showing missing wait for skipped route

   • Keeps the command output available without making the summary code-heavy.

   

   _{Ran code and verified through T-Rex}

   

_{Reviews (1): Last reviewed commit: "Merge pull request #446 from ACM-VIT/cur..." | Re-trigger Greptile}

[greptile-apps]

Wire test into CI

This new regression test is not invoked by any package script or workflow, so it will not run during the normal build checks. A future change can reintroduce HTML caching or prefetch persistence while CI still passes. Please add a package script for this file and run it from the existing CI/build check path.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

Artifacts

Repro: normal npm build validation output omits the service worker cache policy script

• Keeps the command output available without making the summary code-heavy.

Repro: CI-equivalent install and build attempt timed out during dependency installation

• Keeps the command output available without making the summary code-heavy.

Repro: standalone service worker cache policy script passes when invoked directly

• Keeps the command output available without making the summary code-heavy.

_{Ran code and verified through T-Rex}