Add loading indicator to sidebar links (#4693)

* add loading indicator to sidebar links

* fix clicking on same route whould show indicator

* maybe final?

* handle routeChangeError as well as cleaning up timeout

* clearing timeout before creating one instead of routeChangeError

* rm unused

* add license header

* Update usePendingRoute.ts

Co-authored-by: dan <dan.abramov@gmail.com>

beta/src/components/Layout/Sidebar/SidebarLink.tsx

@@ -21,6 +21,7 @@ interface SidebarLinkProps {
   isExpanded?: boolean;
   isBreadcrumb?: boolean;
   hideArrow?: boolean;
+  isPending: boolean;
 }
 
 export function SidebarLink({
@@ -32,6 +33,7 @@ export function SidebarLink({
   isExpanded,
   isBreadcrumb,
   hideArrow,
+  isPending,
 }: SidebarLinkProps) {
   const ref = React.useRef<HTMLAnchorElement>(null);
   const isMobile = useIsMobile();
@@ -67,8 +69,11 @@ export function SidebarLink({
               !selected && !heading,
             'text-base text-link dark:text-link-dark bg-highlight dark:bg-highlight-dark border-blue-40 hover:bg-highlight hover:text-link dark:hover:bg-highlight-dark dark:hover:text-link-dark':
               selected,
+            'dark:bg-gray-60 bg-gray-3 dark:hover:bg-gray-60 hover:bg-gray-3':
+              isPending,
           }
         )}>
+        {/* This here needs to be refactored ofc */}
         {title}
         {isExpanded != null && !heading && !hideArrow && (
           <span

beta/src/components/Layout/Sidebar/SidebarRouteTree.tsx

@@ -11,6 +11,7 @@ import {useRouteMeta} from '../useRouteMeta';
 import {SidebarLink} from './SidebarLink';
 import useCollapse from 'react-collapsed';
 import {useLayoutEffect} from 'react';
+import usePendingRoute from 'hooks/usePendingRoute';
 
 interface SidebarRouteTreeProps {
   isMobile?: boolean;
@@ -77,8 +78,9 @@ export function SidebarRouteTree({
 }: SidebarRouteTreeProps) {
   const {breadcrumbs} = useRouteMeta(routeTree);
   const {pathname} = useRouter();
-  const slug = pathname;
+  const pendingRoute = usePendingRoute();
 
+  const slug = pathname;
   const currentRoutes = routeTree.routes as RouteItem[];
   const expandedPath = currentRoutes.reduce(
     (acc: string | undefined, curr: RouteItem) => {
@@ -121,6 +123,7 @@ export function SidebarRouteTree({
               <SidebarLink
                 key={`${title}-${path}-${level}-link`}
                 href={pagePath}
+                isPending={pendingRoute === pagePath}
                 selected={selected}
                 level={level}
                 title={title}
@@ -143,6 +146,7 @@ export function SidebarRouteTree({
         return (
           <li key={`${title}-${path}-${level}-link`}>
             <SidebarLink
+              isPending={pendingRoute === pagePath}
               href={pagePath}
               selected={selected}
               level={level}

beta/src/hooks/usePendingRoute.ts

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ */
+
+import {useRouter} from 'next/router';
+import React from 'react';
+
+const usePendingRoute = () => {
+  const {events} = useRouter();
+  const [pendingRoute, setPendingRoute] = React.useState<string | null>(null);
+  const currentRoute = React.useRef<string | null>(null);
+  React.useEffect(() => {
+    let routeTransitionTimer: any = null;
+
+    const handleRouteChangeStart = (url: string) => {
+      clearTimeout(routeTransitionTimer);
+      routeTransitionTimer = setTimeout(() => {
+        if (currentRoute.current !== url) {
+          currentRoute.current = url;
+          setPendingRoute(url);
+        }
+      }, 100);
+    };
+    const handleRouteChangeComplete = () => {
+      setPendingRoute(null);
+      clearTimeout(routeTransitionTimer);
+    };
+    events.on('routeChangeStart', handleRouteChangeStart);
+    events.on('routeChangeComplete', handleRouteChangeComplete);
+
+    return () => {
+      events.off('routeChangeStart', handleRouteChangeStart);
+      events.off('routeChangeComplete', handleRouteChangeComplete);
+      clearTimeout(routeTransitionTimer);
+    };
+  }, []);
+
+  return pendingRoute;
+};
+
+export default usePendingRoute;