React js useCallback Hook Tutorial with Example
In this tutorial i will discuss about react hook useCallback. The react hook useCallback returns a memoized callback. Wrapping a component with React.Memo() signals the intent to reuse code. This does not automatically extend to functions passed as parameters.
Remember
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useCallback returns a memoized version of a callback.
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useCallback accepts as arguments a callback and a dependencies array.
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The callback only changes if one of the dependencies has changed.
useCallback example
The following example will clear your concept of useCalback hook!
In the above example, the parent component, < Age / >, is updated (and re-rendered) whenever the Get older button is clicked.
And also consequently, the < Instructions / > child component is also re-rendered because the doSomething prop is passed a new callback with a new reference.
Point to be noted that even though the Instructions child component uses React.memo to optimize performance, it is still re-rendered.
So now how can this be fixed to prevent < Instructions / > from re-rendering needlessly?
useCallback with referenced function
Read also : React js useEffect Hook Tutorial with Example
Hope it can help you.
