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Note that derived state must set be inside a condition like `prevCount !== count`, and there must be a call like `setPrevCount(count)` inside of it. Otherwise, your component would re-render in a loop until it crashes. |
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Note that derived state must set be inside a condition like `prevCount !== count`, and there must be a call like `setPrevCount(count)` inside of it. Otherwise, your component would re-render in a loop until it crashes. |
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If you can, try to avoid derived state. However, derived state is better than updating state in an effect. When you call the `set` function during render, React will render that component immediately after your component exits with a `return` statement. React will ignore the initial output so it won't need to render the children twice. |
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If you can, try to avoid derived state. However, derived state is better than updating state in an effect. When you call the `set` function during render, React will re-render that component immediately after your component exits with a `return` statement, and before rendering the children. This way, children don't need to render twice. |