What global error hooks exist in browsers/Node, and what should they do vs not do?

Short Interview Answer

Browsers: `window.onerror`, `unhandledrejection`. Node: `uncaughtException`, `unhandledRejection`. Use for logging/telemetry; don't use as normal control flow.

Detailed Explanation

Global handlers are safety nets for unexpected failures — report to Sentry/etc., show a generic recovery UI, and in Node often exit on uncaughtException because state may be corrupt. Prefer local handling for expected paths. Ensure handlers themselves don't throw. Filter noisy aborted fetches. Include release/version metadata. For SPAs, pair with route-level boundaries. Document that covering every error globally does not replace thoughtful API design.

Example

window.addEventListener('unhandledrejection', (e) => {
  report(e.reason);
});

Interview Tip

Say 'last resort, not business logic'.

Common Mistake

Swallowing unhandledrejection without logging, hiding production bugs.