React Native Case Studies & Practical Application 2

Question 1

A social media app needs to display an infinite feed of posts with images. Which component combination is most appropriate?

Accepted Answer

FlatList with optimized keyExtractor and getItemLayout

Answer

FlatList with keyExtractor and getItemLayout enables efficient recycling and avoids measuring overhead for uniform-height rows.

Question 2

A food delivery app must show the user's live location on a map updating every 3 seconds. What is the best approach?

Accepted Answer

Use Geolocation.watchPosition and update state on each callback

Answer

watchPosition streams continuous location updates and is more battery-efficient than polling with setInterval.

Question 3

An e-commerce checkout screen freezes briefly when calculating order totals. The calculation is CPU-intensive. What is the recommended fix?

Accepted Answer

Run the calculation in a native module on a background thread

Answer

CPU-intensive JavaScript work should be offloaded to a native module's background thread to keep the JS thread free for UI updates.

Question 4

A messaging app stores thousands of chat messages locally. Which storage solution handles relational queries and large datasets best?

Accepted Answer

SQLite via a library like react-native-quick-sqlite

Answer

SQLite supports structured relational queries, indexes, and handles large datasets efficiently without loading everything into memory.

Question 5

A news app shows articles with HTML content received from an API. What is the safest way to render this content?

Accepted Answer

Render with a WebView using the html prop and origin whitelist

Answer

WebView with a restricted originWhitelist safely sandboxes HTML rendering without exposing the app to script injection.

React Native Practice Test