Production testing produced a small DevTools requirement: find one speculative load in a long list.
Status: 🎉 Landed
Testing Prerender Until Script
At krone.at, article navigation is a useful place to evaluate speculative loading. The site joined the Prerender Until Script origin trial, which allows a page to be prerendered while delaying JavaScript execution until activation.
That reduces the script side effects a site has to account for during speculation, while still doing much of the navigation work ahead of time.
The Debugging Problem
The Speculation Rules panel in Chrome DevTools lists prefetch and prerender attempts. On a page with many candidate article links, the list quickly becomes difficult to inspect:
- no text filter for a route or URL fragment;
- no quick way to isolate a failed attempt;
- repeated visual scanning while adjusting rules.
Debugging why /artikel/12345 was not prerendered meant searching a long list by hand.
The Fix
After discussing the UI with Barry Pollard, the panel gained a text filter using the existing DevTools filtering patterns.
Bug: 479524246
What It Changes
The filter helps with the ordinary questions that come up while testing speculation rules:
- Which URLs were considered?
- Did a specific route prefetch or prerender?
- Which attempts failed?
- Did a rule change affect the intended section of the site?
The change is intentionally small. The panel already had the relevant status and URL data; it only needed a way to narrow the visible rows.
Collaboration
Barry helped validate the interaction and align it with existing DevTools conventions. Testing on a production site supplied the scale that made the missing filter noticeable, while review kept the solution consistent with the rest of DevTools.