withOptional

withOptional.tsx

type NullPartial<T> = {
  [P in keyof T]?: T[P] | null;
};
type Optional<T, K extends keyof T> = Omit<T, K> & NullPartial<T>;

function withOptional<TProps, TOpts extends Array<keyof TProps>>(
  Wrapped: ComponentType<TProps>,
  optionals: TOpts,
  Placeholder: ComponentType<Optional<TProps, TOpts[number]>>,
): ComponentType<Optional<TProps, TOpts[number]>> {
  return props => {
    if (optionals.some(f => props[f] == null)) {
      return <Placeholder {...props} />;
    }
    return <Wrapped {...(props as TProps)} />;
  };
}