Function update

packages/core/src/hooks/useSpring.test.tsx:456–457

(...args: [Args[0], Args[1]?])

  type Args = Parameters<typeof useSpring>
  const update = (...args: [Args[0], Args[1]?]) =>
    renderWithContext((prevElem = <Component args={args} />))

  return [update, context] as const
}