React · Senior · Question 29 of 75

When is it acceptable to call `setState` directly during render?

✓Correct answer: To adjust state when a prop changes, with a guard condition against loops
2Never: it always causes a "Too many re-renders" error
3Always, whenever you need to sync any state with new props

Explanation

The "storing information from previous renders" pattern: if (items !== prevItems) { setPrevItems(items); setSelection(null); }. React immediately re-runs the component's render without painting the intermediate state. It's better than useEffect, but key or computing during render is even better.

When is it acceptable to call `setState` directly during render?

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When is it acceptable to call setState directly during render?

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Test yourself

When is it acceptable to call `setState` directly during render?