v151 · capabilities · performance

API Safety Harness

12 edge-case tests covering API availability, value shape, repeated reads, companion APIs (hardwareConcurrency, deviceMemory), integration with prefers-reduced-motion, graceful fallback patterns, and tier-gated feature-flag logic. All tests run in-page — no server required.

12 tests
0 pass
0 warn
0 fail

fingerprinting budget

Compare the coarse CPU tier with companion hints a site may already see. The API should add a small bucketed signal, not a device-model fingerprint.

    // test log will appear here

    see also

    implementation reference

    Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗