React Native React Native 4

Question 1

In React Native, what is the purpose of `InteractionManager.runAfterInteractions()`?

Accepted Answer

Schedules code to run after all pending animations and interactions complete

Answer

InteractionManager.runAfterInteractions defers expensive work until animations and touch interactions have finished, keeping the UI responsive.

Question 2

What is the correct way to apply platform-specific styles in React Native using StyleSheet?

Accepted Answer

Using Platform.select() inside the style object

Answer

Platform.select({ ios: {}, android: {} }) inside a StyleSheet.create call returns the appropriate style object for the current platform.

Question 3

How does React Native's `PanResponder` differ from the `Gesture` API in react-native-gesture-handler?

Accepted Answer

PanResponder is a JS-thread-based responder system; Gesture handler runs gesture recognition natively

Answer

PanResponder processes gestures in the JS thread and can suffer from lag, while react-native-gesture-handler runs recognition natively for better performance.

Question 4

Which prop on Image component controls how the image is resized to fit its container in React Native?

Accepted Answer

resizeMode

Answer

The resizeMode prop (values: cover, contain, stretch, repeat, center) controls how an Image scales within its bounds.

Question 5

What is Hermes in the context of React Native?

Accepted Answer

A lightweight JavaScript engine optimized for React Native mobile apps

Answer

Hermes is an open-source JavaScript engine built by Meta, optimized for React Native with faster startup times and lower memory usage.

React Native Practice Test

React Native Practice Test

React Native React Native 4