Preact 11.0.0 loading report across Node.js, Bun and Deno

[siddiksawani]

I maintain CompatLab, an open-source npm loading checker, and wanted to share the Preact 11.0.0 report for feedback on how it presents optional-peer requirements.

The result is more specific than a single compatibility badge:

• All eight root checks passed: import and require on Node.js 24.21.0, Node.js 26.10.0, Bun 1.4.2 and Deno 2.9.7.
• Each runtime/mode loaded 12 of the 14 tested subpaths.
• The two failing subpaths were preact/compat/server and preact/compat/server.browser. The Node evidence says it cannot find preact-render-to-string, which was absent from the prepared snapshot.

That missing optional peer matters when reading the report: these results do not establish an SSR defect or a Bun/Deno incompatibility. They describe what happens when loading the published package under this particular setup. No rendering or application tests ran.

The checks use Linux amd64, pinned runtime images, disabled install scripts and no network during execution. The report includes the coverage and structured evidence.

Would a separate “optional peer required” explanation make this more useful to Preact users? I would appreciate corrections to the interpretation or suggestions for showing the environment requirements without implying Preact is broken.

Source · Methodology

[rschristian]

Would a separate “optional peer required” explanation make this more useful to Preact users?

I don't think there's going to be a relevant number of Preact users looking at this particular app, but in the general case, you probably should look out for module resolution errors caused by missing optional peer deps, yes. This is how the ecosystem works, you wouldn't use those subpaths while intentionally not having the requisite peer dep.

[siddiksawani]

Thanks, that makes sense. I've implemented and deployed this in PR #29.

Missing optional peers now show as unmet prerequisites, with the peer name and required version range. The affected compatibility result is inconclusive. This requires a declared optional peer, confirmation that it is absent from the installed snapshot, and a matching missing-dependency error. The original loading observations are preserved.

The fresh Preact 11.0.0 report has 104 successful loading attempts and 13 limited by missing optional peers. Three Bun failures remain unexplained, and the report now makes that explicit. Thanks for pointing this out.

[rschristian]

Might be this: #5304

[siddiksawani]

Thanks for looking into this and fixing the file extension in #5304. I checked the release dates: 11.0.1 was published before that change, so our current report doesn't test the fix yet. I appreciate you following up on the result.