15 Performance questions from the React Native bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
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A.retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
B.an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
C.wasted component updates caused by new object or function identities, mitigated with memoization and stable references
D.the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
Answer + AI explanation with Pro
2. Which term means: "the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container"?
Mid
A.InteractionManager
B.getItemLayout
C.virtualization
D.memory leak
Answer + AI explanation with Pro
3. Which statement is correct?
Mid
A.virtualization — retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
B.virtualization — wasted component updates caused by new object or function identities, mitigated with memoization and stable references
C.virtualization — an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
D.virtualization — the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
Answer + AI explanation with Pro
4. What is unnecessary re-renders?
Senior
A.wasted component updates caused by new object or function identities, mitigated with memoization and stable references
B.the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
C.retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
D.the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
Answer + AI explanation with Pro
5. Which term means: "wasted component updates caused by new object or function identities, mitigated with memoization and stable references"?
Senior
A.unnecessary re-renders
B.getItemLayout
C.virtualization
D.InteractionManager
Answer + AI explanation with Pro
6. Which statement is correct?
Senior
A.unnecessary re-renders — wasted component updates caused by new object or function identities, mitigated with memoization and stable references
B.unnecessary re-renders — the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
C.unnecessary re-renders — an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
D.unnecessary re-renders — the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
Answer + AI explanation with Pro
7. What is getItemLayout?
Mid
A.wasted component updates caused by new object or function identities, mitigated with memoization and stable references
B.the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
C.an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
D.the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
Answer + AI explanation with Pro
8. Which term means: "an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast"?
Mid
A.memory leak
B.getItemLayout
C.unnecessary re-renders
D.virtualization
Answer + AI explanation with Pro
9. Which statement is correct?
Mid
A.getItemLayout — an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
B.getItemLayout — the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
C.getItemLayout — retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
D.getItemLayout — the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
Answer + AI explanation with Pro
10. What is InteractionManager?
Senior
A.the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
B.an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
C.retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
D.the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
Answer + AI explanation with Pro
11. Which term means: "the API that defers expensive work until after animations and gestures finish, keeping the interface responsive"?
Senior
A.InteractionManager
B.memory leak
C.getItemLayout
D.virtualization
Answer + AI explanation with Pro
12. Which statement is correct?
Senior
A.InteractionManager — an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
B.InteractionManager — retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
C.InteractionManager — wasted component updates caused by new object or function identities, mitigated with memoization and stable references
D.InteractionManager — the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
Answer + AI explanation with Pro
13. What is memory leak?
Senior
A.wasted component updates caused by new object or function identities, mitigated with memoization and stable references
B.retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
C.the technique of rendering only items near the viewport and recycling others, the core reason a windowed list beats a plain scroll container
D.an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
Answer + AI explanation with Pro
14. Which term means: "retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts"?
Senior
A.unnecessary re-renders
B.InteractionManager
C.virtualization
D.memory leak
Answer + AI explanation with Pro
15. Which statement is correct?
Senior
A.memory leak — an optional list prop that supplies fixed row dimensions up front, letting the list skip measurement and jump to any index fast
B.memory leak — wasted component updates caused by new object or function identities, mitigated with memoization and stable references
C.memory leak — the API that defers expensive work until after animations and gestures finish, keeping the interface responsive
D.memory leak — retained references that prevent garbage collection, often from timers or listeners not cleared when a screen unmounts
Answer + AI explanation with Pro
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