Discussion on: TypeScript All the Things!

If you know better than the typechecker, you can use ! to assert that something will not be null or undefined:

export default function MindMap({ data }: Props) {
  const divRef: RefObject<HTMLDivElement> = createRef();
  useEffect(() => {
    renderMindMap(divRef.current!, data);
  }, [divRef, data]);
  return <div ref={divRef} />;
}

Note the divRef.current!. For all its advanced capabilities, TypeScript does make it very easy for you to ignore its analysis!