Final assessment

Twelve questions across the whole course. Score 70% or more to pass and unlock your certificate. You can retake it as often as you like.

Finish every lesson to earn the certificate — you can take the assessment any time.

Which description of Trailhead’s architecture is accurate?

React components render HTML that a WebView displays.
Swift and Kotlin code is generated from your JSX at build time.
JavaScript runs on the UI thread and draws directly to the screen.
JavaScript runs in Hermes on its own thread, and the Fabric renderer creates native views that the UI thread draws.

A new hike card looks squashed: the title overflows and pushes the date badge off screen. The row is flexDirection: 'row'. Which change is idiomatic?

Give the title width: 200.
Give the badge position: 'absolute'.
Give the title’s container flex: 1 and the Text numberOfLines={1}.
Switch the row to flexDirection: 'column'.

Which list setup is right for 1,000 hikes grouped by month with sticky headers?

A ScrollView with nested .map() calls for months and hikes.
A SectionList with sections shaped { title, data } and a keyExtractor returning each hike’s id.
One FlatList per month inside a ScrollView.

Trailhead’s Stats tab is part of a (tabs) group, and hikes/[id] is in the root Stack. A user on Stats opens a hike and swipes back. Where do they land?

On the Stats tab, with its scroll position intact.
On the first tab, because the tab group resets.
On the sign-in screen.
Nowhere; detail screens in the root Stack can’t be swiped back.

What is the main reason Trailhead keeps parsing and validation in pure functions like parseDistanceKm and validateHikeForm?

Pure functions run on the UI thread, so they’re faster.
React Native requires validation to live outside components.
They can be tested in milliseconds with plain Jest, without devices, mocks or rendering.
They make the JavaScript bundle smaller.

A deep link opens trailhead://hikes/9999, but that hike doesn’t exist. What should happen?

The app crashes, which is acceptable for invalid links.
The detail screen shows a clear “hike not found” message with a way back to the log.
Expo Router silently redirects to +not-found.tsx because the id is unknown.

Trailhead must remember the sign-in token, 600 hikes, and the user’s preferred units. Which mapping is right?

All three in AsyncStorage under separate keys.
All three in expo-secure-store.
Token in SQLite, hikes in AsyncStorage, units in SecureStore.
Token in expo-secure-store, hikes in expo-sqlite, units in AsyncStorage.

When is the best moment for Trailhead to ask for camera permission?

On first launch, together with location and notifications, to get it over with.
Never; expo-image-picker doesn’t need permission for the camera.
When the user taps “Take photo” on a hike, after a short explanation if needed.
After the user has logged ten hikes, as a reward.

A tracking screen starts watchPositionAsync in an effect. Which cleanup is correct?

Store the subscription and call subscription.remove() in the effect’s cleanup, handling the case where it arrives after unmount.
Call Location.stopAllAsync() when the app goes to the background.
No cleanup is needed; React Native stops native subscriptions on unmount.

You need to know which components re-render while scrolling Trailhead’s log. Which tool answers that directly?

LogBox
The Profiler in React Native DevTools, recording why each component rendered.
The Xcode console
eas build --profile development

Which sequence ships Trailhead’s first version to the App Store?

eas update --channel production, then wait for review.
npx expo start --no-dev, then upload the QR code to App Store Connect.
eas submit, then eas build --profile production.
eas build --platform ios --profile production, then eas submit --platform ios, test in TestFlight, then submit for review.

A crash in Trailhead’s comma parsing reaches production. Which response is fastest while staying safe?

Remove the app from the store until a new version passes review.
Publish the fix directly to production without testing to save time.
Fix and test it, publish with eas update to the preview channel, verify on a real phone, then publish to production.
Raise the runtime version so the fix reaches all builds.

12 questions unanswered