Transforming result data, may lead to performance issues?

[jdolinski1]

Hello, in our codebase we are wrapping useSWR hook and it's result with our custom function that offers optional transformation via function in parameters.

export const useFetchGQL = <TData, TMappedData = TData>(
    query: string,
    variables: Maybe<object>,
    mapFn?: (data: TData) => TMappedData
): UseFetchRes<TData> | UseFetchRes<TMappedData> => {
    const headers = useSelector(getHttpHeaders)
    const shouldFetch = !!variables

    const result = useSWR(shouldFetch ? [query, headers, variables] : null, graphqlFetcher)

    return useMemo(() => {
        if (mapFn) {

            // May this transformation of 'data' attribute cause any troubles?
            return {
                ...result,
                ...(result.data ? { data: mapFn(result.data) } : null),
            } as UseFetchRes<TMappedData>
        }

        return result as UseFetchRes<TData>
    }, [mapFn, result])
}

I was thinking whether the code above might break or cause any performance issues?
E.g. performance optimizations mentioned here: https://swr.vercel.app/docs/advanced/performance#dependency-collection

Thanks,
Jiri