15 real Performance questions from the React Native bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is virtualization?
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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
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"?
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
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
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"?
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
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