converts NavDrawer, NavDrawerGroup, and NavDrawerFlyout to TypeScript

src/components/list_group/list_group_item.tsx

@@ -113,7 +113,7 @@ export type EuiListGroupItemProps = CommonProps &
      * Pass-through ref reference specifically for targeting
      * instances where the item content is rendered as a `button`
      */
-    buttonRef?: React.RefObject<HTMLButtonElement>;
+    buttonRef?: React.Ref<HTMLButtonElement>;
   };
 
 export const EuiListGroupItem: FunctionComponent<EuiListGroupItemProps> = ({

src/components/nav_drawer/index.ts

@@ -0,0 +1,6 @@
+export { EuiNavDrawer, EuiNavDrawerProps } from './nav_drawer';
+export { EuiNavDrawerGroup, EuiNavDrawerGroupProps } from './nav_drawer_group';
+export {
+  EuiNavDrawerFlyout,
+  EuiNavDrawerFlyoutProps,
+} from './nav_drawer_flyout';

src/components/nav_drawer/nav_drawer.test.js → src/components/nav_drawer/nav_drawer.test.tsx

@@ -2,15 +2,16 @@ import React from 'react';
 import { render } from 'enzyme';
 
 import { EuiNavDrawer } from './nav_drawer';
-import { EuiNavDrawerGroup } from './nav_drawer_group';
+import { EuiNavDrawerGroup, FlyoutMenuItem } from './nav_drawer_group';
+import { EuiListGroupItemProps } from '../list_group';
 
-const extraAction = {
+const extraAction: EuiListGroupItemProps['extraAction'] = {
   color: 'subdued',
   iconType: 'pin',
   iconSize: 's',
 };
 
-const topLinks = [
+const topLinks: FlyoutMenuItem[] = [
   {
     label: 'Recently viewed',
     iconType: 'clock',
@@ -74,7 +75,7 @@ const topLinks = [
   },
 ];
 
-const exploreLinks = [
+const exploreLinks: FlyoutMenuItem[] = [
   {
     label: 'Canvas',
     href: '#',