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conformance · v151
v151 · declarative-performance-observer — conformance probe
9 assertions drawn from the spec. Each is a single contract the spec text makes. Pass/fail reflects what this browser executed; blocked means the contract was not run because it needs user mediation, hardware, or another unavailable precondition. Open the page in Chrome stable / canary / Firefox / Safari to compare.
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pass
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fail
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| id | contract | kind | verdict | detail |
|---|---|---|---|---|
performance-observer-exists |
PerformanceObserver, the JavaScript API the declarative header mirrors, is a constructor. spec ↗ | typeof | … | |
supported-entry-types-exposed |
PerformanceObserver.supportedEntryTypes is exposed as an array — the exact list the header's entry-types directive draws from. spec ↗ | script | … | |
navigation-entry-type-supported |
The navigation entry type named by the explainer's example header is observable. spec ↗ | script | … | |
mark-entry-type-supported |
The mark entry type used by the include-user-timing directive is observable. spec ↗ | script | … | |
visibility-state-entry-type-supported |
The visibility-state entry type named in the explainer's example header is observable. spec ↗ | script | … | |
user-timing-mark-returns-entry |
performance.mark() returns a PerformanceMark whose detail round-trips, as required for marks synced by include-user-timing. spec ↗ | script | … | |
session-end-entry-type-proposed |
The proposed PerformanceSessionEndTiming entry (entryType 'session-end') appears in supportedEntryTypes. Expected to FAIL until the pre-incubation proposal ships in a browser; a pass means the proposal's key new surface has landed. spec ↗ | script | … | |
reporting-observer-exists |
The Reporting API's ReportingObserver interface — the delivery mechanism the header integrates with — exists. spec ↗ | typeof | … | |
header-echo-emits-structured-header |
The feature's headline HTTP contract: the header-echo route responds with a real Performance-Observer header carrying the explainer's structured-field directives (report-to, the requested entry-types, include-user-timing, capture-early-failures) plus a Reporting-Endpoints header naming the telemetry endpoint. spec ↗ | script | … |