memo

memo let's you skip re-rendering a component if its props did not change. The component returned from the memo function is said to be memoized. Normally in React all child components are re-rendered when their parent component re-renders, that is not the case for memoized components as long as their props haven't changed.

memo(Component, arePropsEqual?)

The second argument arePropsEqual let's you supply a function with custom logic to evaluate equality. The default equality comparison uses Object.is.

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