Reliability & Monitoring: Recap And Verify

5 questions. Answer all of them, then submit; you need 4 of 5 to pass.

1. 1. How do you fire a tag when an uncaught JavaScript error happens on the page?

   The JavaScript Error trigger, which fires on gtm.pageError, with the Error built-in variables carrying the detailsAn All Elements trigger on the consoleA Custom HTML tag that overrides console.errorA Timer trigger that samples window.errors
2. 2. Your JavaScript Error trigger is live, but failures in async code with rejected promises never appear. Why?

   Async errors fire the trigger twice and cancel outUnhandled promise rejections are a separate browser event the JavaScript Error trigger does not cover; you need a listener that pushes an event for themThe Error built-in variables are disabledPromise rejections only occur in preview mode
3. 3. What is the pattern for getting Core Web Vitals like LCP and CLS into GA4 via GTM?

   Enable the Web Vitals built-in triggerGA4 collects Web Vitals automatically through Enhanced MeasurementA PerformanceObserver in a listener pushes a web_vitals event with metric name and value, and a GA4 Event tag sends itRead performance.timing in a trigger condition
4. 4. GTM has no built-in trigger for a browser signal you care about. What is the general recipe this module keeps reusing?

   Request the trigger type from Google and wait for the releasePoll for the condition with a Timer triggerUse an All Elements trigger with a Custom JavaScript conditionA Custom HTML listener translates the browser event into a dataLayer push, and a Custom Event trigger fires tags on it
5. 5. Your error tag fires, but the events arrive in GA4 with no detail about what broke. What did you forget?

   To enable the Error Message, Error URL and Error Line built-in variables and map them as event parametersTo set the tag to fire Once per pageTo add an exception trigger for errorsTo wrap the site in a try/catch block