@zeruxjs/performance

Browser performance observations, resource hints, cache validators, reporting, and optional Lighthouse auditing.

const collector = createVitalCollector({maxPerMetric:200});
const stop = observeWebVitals({onMetric:metric => collector.record(metric)});
const reporter = createVitalReporter({url:'https://metrics.example.com/vitals', maxBatch:50});
for (const summary of collector.snapshot()) console.log(summary.name, summary.p75);
// Add consent-approved metrics with reporter.add(metric); await reporter.flush().
stop(); reporter.destroy();

observeWebVitals observes browser LCP, CLS, FCP and navigation TTFB, and stops observers when disposed. It does not claim spec-accurate INP; browser support, page lifecycle, and metric accuracy vary. createVitalCollector retains bounded percentile samples, and createVitalReporter sends bounded JSON batches through an explicit fetch call, defaulting to omitted credentials and retrying a failed batch in memory. Callers are responsible for consent, privacy and opting into any telemetry. No tracking starts on import.

auditLighthouse(url, {port, runner}) uses an already-running Chrome debugging port (default 9222). It loads lighthouse lazily and does not install/start Chrome; its runner can be injected for testing. Cache ETags support weak and strong matching separately.

Release 0.0.2

Prepared to validate npm trusted publishing through GitHub Actions.

Public static-page navigation prefetch

import {installNavigationPrefetch} from '@zeruxjs/performance/navigation';
const navigation=installNavigationPrefetch({paths:['/zeruxjs/'],maxPages:6,delayMs:120});
// On SPA/component teardown:
navigation.destroy();

The browser-safe navigation entry point uses intent (hover/focus), bounded unique URLs, same-origin public path prefixes, and speculation-rule prefetch with a rel=prefetch fallback. It does not prerender/execute destination pages. Queries, downloads, external links, nofollow links, data-no-prefetch ancestors and same-page anchors are excluded. Saving data, slow connections (3g or slower), offline state and hidden documents suppress new requests. The optional nonce permits speculation rules under a compatible CSP; use strategy:'link' when your policy does not permit inline speculation rules. Browser policy can still decline a hint. queued reports submitted hints, not proof of a completed/cached network request.

Only pass prefixes that contain public, side-effect-free static HTML; this helper is not an authorization or URL-classification mechanism for application APIs. It reads browser globals only at installation and returns an inert controller on the server. destroy() removes its listeners, pending timer and injected elements. No metrics, cookies or identifiers are collected.

Release 0.0.3

Synchronized ecosystem release, including Zuixs CSS-entry support and documentation updates. Existing placeholder packages retain their documented limitations.