Comparison questionHard~10 min

Interview question

What belongs in an Angular ErrorHandler, and what should be handled closer to the failure?

Handles expected failures at their callsite and reserves ErrorHandler for reporting unexpected framework or global failures with useful context.

1Say itAnswer out loud first

2CompareCompare with Core answer

3RefineRefine with Stronger and Advanced

TL;DR

I handle expected API, validation, and workflow failures where the operation is started so the UI can recover with the right context. Angular's ErrorHandler is for unexpected errors the framework forwards, and a custom handler can report them to observability infrastructure. It should not turn every failure into the same toast or pretend the application recovered when its state may be invalid.

Full answer below

Practice focus

Angular ErrorHandler, global error listeners, RxJS errors, recovery, observability, privacy, and error boundaries.

Answer first

Answer path

Core answer first, then checkpoints toward a stronger answer.

Start
Core answer
Start here. This is the direct spoken answer to practice first.
Overview
The code that initiated an expected operation usually has the context to recover; a global handler usually does not.
I handle expected API, validation, and workflow failures where the operation is started so the UI can recover with the right context. Angular's ErrorHandler is for unexpected errors the framework forwards, and a custom handler can report them to observability infrastructure. It should not turn every failure into the same toast or pretend the application recovered when its state may be invalid.
Checkpoint
Stronger answer
Optional upgrade with examples, trade-offs, and sharper phrasing.
The report includes release, route template, browser context, feature, and a normalized stack while excluding tokens, request bodies, and user-entered data. Browser error and unhandledrejection listeners cover failures outside Angular's normal call path when configured. RxJS streams use local catchError only where there is a meaningful fallback; otherwise the error remains visible. A fatal screen can offer reload or safe navigation while a local panel failure remains local.
Finish
Advanced answer
Optional deeper angle for production judgment and nuance.
I deduplicate repeated errors, sample noisy signatures, and preserve causality so one root failure does not create a telemetry storm. Source maps are access-controlled and release-aligned so production stacks can be resolved without shipping private source indiscriminately. Alerts are based on affected users and regression rate, not raw console volume. Tests verify both recovery behavior and reporting failure, because telemetry must never create another user-facing exception loop.

Review signals

Use these to catch weak phrasing, shallow reasoning, and risky claims.

Common mistakesCandidateCommon mistakesMistakes that weaken the answer or signal shallow understanding.Open details

Details

Using ErrorHandler as the normal API error path.
Sending full application state and user input with every exception.
Catching errors and returning an empty value without a defined fallback.

Red flagsCandidateRed flagsSignals that an interviewer may treat as risky.Open details

Details

One exception produces hundreds of identical reports.
A global handler claims success after unknown state corruption.
Production stacks cannot be associated with a release.

Follow-up prompts

Quick interviewer prompts inside this drill.

Follow-up questionsCandidateFollow-up questionsLikely next questions after the main answer.Open details

Details

Treat these as the next interviewer turn. Answer one out loud, then save the gap in your practice notes.

Which errors should stay local?
What context is safe to report?
How would you avoid an error-reporting loop?

Continue practice

Move to the linked follow-up, next path step, prerequisite, or deeper variant.

1 linked

Next interviewer turn

Continue the conversation with a linked follow-up drill.

Angular deep-link deploymentSeparates runtime application failures from deployment routing failures.

Practice route

Read core answer Review checklist Follow-up prompts Track progress

Finished this drill?

Practice freely. Sign in only when you want to save completion, confidence, notes, or bookmarks.

New to Aporeon? Create account

Drill details

Human editorial direction

Aporeon is shaped by Aleksandar Tomovski, a software developer with experience on both sides of technical interviews. Content is reviewed for accuracy, natural spoken delivery, useful depth, and honest trade-offs.

About the creator Editorial standards

Was this drill useful?