useCallback and useMemo are both React hooks that can be used to optimize the performance of your React application by remembering calculated values in components but there is a slight difference in terms of Return Value, Dependency array. Below is good comparison of both.
Use case: The main use case of useCallback is to remember a function, while the main use case of useMemo is to remember a value.
Return value: useCallback returns a memorized function, while useMemo returns a memorized value.
Dependencies Array:
useCallback takes a dependency array as the second argument, which specifies the values on which the stored function depends. The function will only be recalculated if any value in the dependencies array changes. On the other hand,
useMemo also takes an array of dependencies as the second argument, but it specifies the values on which the remembered value depends. The value will only be recalculated if any value in the dependencies array changes.
Performance Considerations: If you have a computationally expensive function that you need to pass as a prop to a child component, you should use useCallback to remember that function. This will prevent the child component from rendering unnecessarily. If you have a computationally expensive value that you need to use in a component, you should use useMemo to remember that value. This will prevent the value from being unnecessarily recalculated on every new render.
In this example, we use both useMemo and useCallback to remember a value and a function respectively. Expensive value is remembered by useMemo and expensive function is remembered by useCallback. Both hooks depend on the value of the count state and will only recalculate if the count value changes. This can help optimize component performance.
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