@sprint-logger/web

Sprint Signals error logger for bundled browser apps (Next.js, Vite, CRA, Astro). Import and init() once — no <script> tag.

npm i @sprint-logger/web

import { init, capture, captureMessage } from "@sprint-logger/web";

// once, at app start (e.g. Next.js instrumentation-client.ts)
init("sk_sig_xxx", { release: "1.2.3" });

// uncaught errors + unhandled rejections are captured automatically.
// for handled errors:
try { await save(); }
catch (e) { capture(e, { route: "/editor", severity: "high" }); }

API

• init(key, { release?, origin?, installGlobalHandlers?, onError?, detectDeadClicks?, captureHttpErrors?, capturePerf?, captureConsoleErrors? }) — call once. A missing/invalid key is a silent no-op. SSR-safe. The four capture*/detect* flags are v2 auto-detectors, all default true.
• capture(error, { route?, severity?, userToken?, breadcrumbs? }) — manual capture (handled: true).
• captureMessage(message, ctx?) — capture a string.

Capture more than errors (v2)

Signals now catches bugs that never throw — dead/rage clicks, silent HTTP failures, slow ops — through the same pipeline (group → inbox → triage → task → QA closes it). v1 above is unchanged; v2 is additive.

Auto-detectors — on by default via init flags, set false to disable:

• detectDeadClicks — absence-of-effect detector (dead + rage clicks).
• captureHttpErrors — emits an http_error signal on a handled 4xx/5xx (+404).
• capturePerf — emits a perf signal when long-task/LCP/INP/CLS exceeds its Core-Web-Vitals "good" threshold.
• captureConsoleErrors — auto-captures every console.error as a low-severity error signal (retroactively covers caught-and-logged errors, zero edits). May surface existing logs on first upgrade → set false or mute the group if noisy.

Assert an app-level problem the SDK can't infer:

import { captureSignal, startSpan } from "@sprint-logger/web";

// business-invariant violation
captureSignal({ type: "cart.empty-after-add", title: "Cart empty after add", severity: "high" });

// time an op — emits `slow_operation` ONLY if it exceeds thresholdMs (default 1000)
const span = startSpan("checkout.submit", 1500);
await submit();
span.finish({ items: cart.length });

• captureSignal({ type, title, severity?, fingerprint?, context?, route?, userToken? }) — type is the stable low-cardinality fingerprint seed.
• startSpan(op, thresholdMs?) → { finish(extra?) }.

React 19 boundary bridge — boundary-caught render errors never reach window.onerror, so wire once:

import { signalsReactErrorHandler } from "@sprint-logger/web";
createRoot(el, { onCaughtError: signalsReactErrorHandler(), onUncaughtError: signalsReactErrorHandler() });

Privacy

Pseudonymous only. Sends message, normalized stack, an opaque per-browser userToken (never an email/name/IP), route/release, and non-identifying env (platform, OS, browser, device, timezone, locale, viewport, network, handled, error type). The server rejects PII.

The sk_sig_… key is a project selector, not a secret — mint it in your Sprint project's Signals settings.

MIT