Function createElementHook

packages/core/src/element.ts:24–68

(
  createElement: (
    props: P,
    context: LeafletContextInterface,
  ) => LeafletElement<E>,
  updateElement?: (instance: E, props: P, prevProps: P) => void,
)

) => RefObject<LeafletElement<E>>

export function createElementHook<E, P, C = unknown>(
  createElement: (
    props: P,
    context: LeafletContextInterface,
  ) => LeafletElement<E>,
  updateElement?: (instance: E, props: P, prevProps: P) => void,
) {
  if (updateElement == null) {
    return function useImmutableLeafletElement(
      props: P,
      context: LeafletContextInterface,
    ): ReturnType<ElementHook<E, P>> {
      const elementRef = useRef<LeafletElement<E, C>>(undefined) as RefObject<
        LeafletElement<E>
      >
      if (!elementRef.current)
        elementRef.current = createElement(props, context)
      return elementRef
    }
  }

  return function useMutableLeafletElement(
    props: P,
    context: LeafletContextInterface,
  ): ReturnType<ElementHook<E, P>> {
    const elementRef = useRef<LeafletElement<E, C>>(undefined) as RefObject<
      LeafletElement<E>
    >
    if (!elementRef.current) elementRef.current = createElement(props, context)
    const propsRef = useRef<P>(props)
    const { instance } = elementRef.current

    useEffect(
      function updateElementProps() {
        if (propsRef.current !== props) {
          updateElement(instance, props, propsRef.current)
          propsRef.current = props
        }
      },
      [instance, props, updateElement],
    )

    return elementRef
  }
}