React Native interviews test whether you understand native rendering, not only JSX. Expect questions on Flexbox column defaults, FlatList vs map-in-ScrollView, the JS/UI thread, and why Text is required. Be ready to discuss Expo vs bare and how you would add a native module.
This React Native cheat sheet is written for people searching for a fast, accurate reference: students, junior developers, and teams shipping production software. Pin it, copy the snippets, and come back when syntax slips.
Quick reference
- Threads: JS runs your React code. UI/native thread commits views. Heavy JS janks animations if you block it.
- New arch: Fabric/JSI reduce bridge serialization. Know that it exists; say what you have shipped.
- Lists: FlatList/FlashList virtualize. Never dump 1k Views in a ScrollView.
- State: Same React rules. Lift state, avoid extra renders on lists (
React.memo, stable extraData). - Styling: StyleSheet + Flexbox column. No DOM CSS.
- Native: Kotlin/Swift modules when a JS library cannot reach a platform API.
- Debug: Logs, React DevTools, Flipper/network, Hermes, crash stack on device.
- Expo: Managed workflow vs prebuild vs bare. Know why you would eject.
Copy-paste examples
Interview FlatList
Be ready to write keyExtractor and renderItem from memory. Mention getItemLayout if rows are fixed height.
import { FlatList, Text } from 'react-native';
export function Titles({ rows }) {
return (
<FlatList
data={rows}
keyExtractor={(item) => String(item.id)}
renderItem={({ item }) => <Text>{item.title}</Text>}
/>
);
}Common mistakes
- Describing RN as “a WebView of the site.”
- Cannot explain why a huge ScrollView of maps dropped frames.
- Using web CSS vocabulary (
position: sticky,vh) as if it applied unchanged. - No plan for offline, permissions, or store builds.
FAQ
- Is React Native the same as React? Same component model and hooks. Different renderer and components. No HTML/CSS DOM.
- Hermes? A JS engine optimized for RN. Faster startup than old JSC on many Android devices. Default in current templates.
- How do you pass data native → JS? Native modules / events. On the new architecture, JSI can expose methods more directly. Name a library you used (camera, maps).
Related React Native cheat sheets
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