React Native Professional Standards & Competencies 2 — Questions and Answers
Question 1: A React Native app's FlatList renders correctly on iOS but shows blank rows on Android. What is the best first debugging step?
- Rebuild the Android bundle from scratch
- Use the React Native Debugger to inspect the FlatList's rendered items and data prop on Android (Correct answer)
- Switch to ScrollView as FlatList has known Android bugs
- Downgrade React Native to a stable LTS version
Correct answer: Use the React Native Debugger to inspect the FlatList's rendered items and data prop on Android
Using React Native Debugger to inspect component state and props isolates whether the issue is data, rendering, or platform-specific styling.
Question 2: Which practice best demonstrates professional code ownership in a React Native team?
- Merging your own pull requests to move faster
- Writing self-reviewing pull requests with context, screenshots, and test evidence (Correct answer)
- Keeping component logic private to avoid review overhead
- Avoiding code comments to keep files clean
Correct answer: Writing self-reviewing pull requests with context, screenshots, and test evidence
Self-documented PRs with context and evidence reduce review friction and demonstrate accountability for the change.
Question 3: When estimating a React Native feature involving a new native module, a professional developer should:
- Give the same estimate as a pure JS feature
- Add a fixed 10% buffer to any estimate
- Include a spike/research phase to assess native bridging complexity before committing (Correct answer)
- Refuse to estimate until the native module is fully built
Correct answer: Include a spike/research phase to assess native bridging complexity before committing
A spike phase lets the team discover unknown native complexities before committing to a timeline, improving estimate accuracy.
Question 4: A junior developer on your team repeatedly submits PRs without running the linter. The most professional response is to:
- Reject every PR without comment until they comply
- Add a pre-commit hook that enforces linting automatically and explain why it helps the team (Correct answer)
- Fix the lint errors yourself to unblock CI
- Escalate to management immediately
Correct answer: Add a pre-commit hook that enforces linting automatically and explain why it helps the team
Automating the constraint removes the human error and explaining the 'why' builds long-term team discipline.
Question 5: Which metric is most professionally relevant when evaluating React Native app performance for end users?
- Bundle size in kilobytes
- JavaScript thread FPS during interactions
- Number of components in the component tree
- Time to Interactive (TTI) measured on mid-range Android devices (Correct answer)
Correct answer: Time to Interactive (TTI) measured on mid-range Android devices
TTI on representative hardware reflects real user experience, not synthetic measures that may not correlate with perceived performance.
Question 6: A stakeholder requests a feature that would require bypassing the App Store review process using dynamic code updates on iOS. What should a professional developer do?
- Implement it quietly since it speeds up delivery
- Explain that Apple's App Store guidelines prohibit executable code downloads that change app behavior and propose compliant alternatives (Correct answer)
- Use a third-party OTA service that claims to be compliant
- Implement it and hope Apple doesn't notice
Correct answer: Explain that Apple's App Store guidelines prohibit executable code downloads that change app behavior and propose compliant alternatives
Apple's guidelines explicitly prohibit dynamically downloaded code that alters app behavior; a professional surfaces compliance risks and proposes alternatives.
Question 7: Which approach best demonstrates professional handling of deprecated React Native APIs in a production app?
- Suppress deprecation warnings in the console
- Continue using deprecated APIs until they are removed
- Create a tracked migration task, document the risk, and schedule replacement before the API is removed (Correct answer)
- Immediately refactor all deprecated APIs before any other work
Correct answer: Create a tracked migration task, document the risk, and schedule replacement before the API is removed
Tracked migration with documented risk balances technical debt management against immediate business priorities without ignoring the issue.
React Native Professional Standards & Competencies 2
A React Native app's FlatList renders correctly on iOS but shows blank rows on Android.
What is the best first debugging step?