useMemo and Derived Values

Do not store in state what you can calculate from other state. Compute it during render. For expensive work, useMemo remembers the result until its inputs change.

Examplereact

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matches is derived from query. There is no separate matches state to keep in sync.

Quick check

What is "derived state"?

State stored in the browserA value calculated from other state during renderState copied from props into useState

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