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.
useCallback returns a memoized version of a callback.
useCallback accepts as arguments a callback and a dependencies array.
The callback only changes if one of the dependencies has changed.
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.