Created
April 25, 2022 09:12
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React Hook: useComponentDidUpdate()
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const useComponentDidUpdate = useGetSnapshotBeforeUpdate( | |
(_prevProps, prevState) => { | |
if (!messagesWrapperRef.current || !messages.data || !prevState) return undefined; | |
if (messagesWrapperRef.current.scrollHeight > (prevState.scrollHeight || 0)) { | |
return prevState.scrollHeight; | |
} | |
return undefined; | |
}, | |
undefined, | |
{ scrollHeight: messagesWrapperRef.current?.scrollHeight }, | |
); | |
useComponentDidUpdate((_prevProps, _prevState, snapshot) => { | |
if (snapshot && messagesWrapperRef.current) { | |
messagesWrapperRef.current.scrollTop = messagesWrapperRef.current.scrollHeight - snapshot; | |
} | |
}); |
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import { useEffect, useLayoutEffect, useRef } from 'react'; | |
const usePrevPropsAndState = <Props, State>(props: Props, state: State) => { | |
const prevPropsAndStateRef = useRef<{ props: Props | null; state: State | null }>({ | |
props: null, | |
state: null, | |
}); | |
const prevProps = prevPropsAndStateRef.current.props; | |
const prevState = prevPropsAndStateRef.current.state; | |
useEffect(() => { | |
prevPropsAndStateRef.current = { props, state }; | |
}); | |
return { prevProps, prevState }; | |
}; | |
export const useGetSnapshotBeforeUpdate = <Props = any, State = any, Snapshot = any>( | |
getSnapshotBeforeUpdateCb: (prevProps: Props | null, prevState: State | null) => Snapshot, | |
props: Props, | |
state: State, | |
) => { | |
// get prev props and state | |
const { prevProps, prevState } = usePrevPropsAndState<Props, State>(props, state); | |
const snapshot = useRef<Snapshot | null>(null); | |
// getSnapshotBeforeUpdate - not run on mount + run on every update | |
const componentJustMounted = useRef(true); | |
useLayoutEffect(() => { | |
if (!componentJustMounted.current) { | |
snapshot.current = getSnapshotBeforeUpdateCb(prevProps, prevState); | |
} | |
componentJustMounted.current = false; | |
}); | |
const useComponentDidUpdate = ( | |
componentDidUpdateCb: ( | |
prevProps: Props | null, | |
prevState: State | null, | |
snapshot: Snapshot | null, | |
) => void, | |
) => { | |
useEffect(() => { | |
if (!componentJustMounted.current) { | |
componentDidUpdateCb(prevProps, prevState, snapshot.current); | |
} | |
}); | |
}; | |
return useComponentDidUpdate; | |
}; |
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