Loading HOC

loading-hoc.tsx

interface WithLoadingProps {
  loading: boolean;
}

const withLoading = <P extends object>(Component: React.ComponentType<P>) =>
  class WithLoading extends React.Component<P & WithLoadingProps> {
    render() {
      const { loading, ...props } = this.props;
      return loading ? <LoadingSpinner /> : <Component {...props as P} />;
    }
  };

This appears to be due to a bug with TypeScript:
microsoft/TypeScript#28938 (comment)

To fix it for now you'll need to use a cast:

<Component {...props as P} />;