fix: types in build demo

.travis.yml

@@ -15,3 +15,4 @@ script:
   - yarn lint
   - yarn test:ci
   - yarn build
+  - yarn build:demo

src/Section.tsx

@@ -3,13 +3,13 @@ import { ScrollContext } from './context';
 
 type Props = {
   id: string;
-  meta: unknown;
+  meta?: unknown;
   children: React.ReactNode;
 } & React.HTMLProps<HTMLButtonElement>;
 
 const Section = ({ id, children, meta, ...rest }: Props) => {
   const { registerRef } = useContext(ScrollContext);
-  const ref = useMemo(() => registerRef({id, meta}), [id]);
+  const ref = useMemo(() => registerRef({ id, meta }), [id]);
 
   return (
     <section {...rest} ref={ref} id={id}>

src/types.d.ts

@@ -7,7 +7,7 @@ type Meta = {
 };
 
 type ScrollContextType = {
-  registerRef: ({id: string, meta: unknown}) => RefObject<HTMLElement> | null;
+  registerRef: ({ id: string, meta: unknown }) => RefObject<HTMLElement> | null;
   scrollTo: (section: string) => void;
   refs: RefsRegister;
   meta: Meta;