From 4468d2974025e10454522699b03ea8b99dfda74e Mon Sep 17 00:00:00 2001
From: Tom Moor <tom.moor@gmail.com>
Date: Tue, 1 Mar 2022 21:51:51 -0800
Subject: [PATCH] perf: Navigation of shared trees feels slow (#3171)

* perf: Navigation of shared trees feels slow

* remove redundant call to setActiveDocument

Co-authored-by: Nan Yu <thenanyu@gmail.com>
---
 app/components/Sidebar/Shared.tsx             |  3 +-
 .../Sidebar/components/SharedDocumentLink.tsx | 16 ++++--
 app/scenes/Document/Shared.tsx                | 51 ++++++++++++++++---
 app/stores/UiStore.ts                         |  8 ++-
 4 files changed, 67 insertions(+), 11 deletions(-)

diff --git a/app/components/Sidebar/Shared.tsx b/app/components/Sidebar/Shared.tsx
index 0fcbc86f9..adfeab23c 100644
--- a/app/components/Sidebar/Shared.tsx
+++ b/app/components/Sidebar/Shared.tsx
@@ -14,7 +14,7 @@ type Props = {
 };
 
 function SharedSidebar({ rootNode, shareId }: Props) {
-  const { documents } = useStores();
+  const { ui, documents } = useStores();
 
   return (
     <Sidebar>
@@ -25,6 +25,7 @@ function SharedSidebar({ rootNode, shareId }: Props) {
             shareId={shareId}
             depth={1}
             node={rootNode}
+            activeDocumentId={ui.activeDocumentId}
             activeDocument={documents.active}
           />
         </Section>
diff --git a/app/components/Sidebar/components/SharedDocumentLink.tsx b/app/components/Sidebar/components/SharedDocumentLink.tsx
index fd1b88e1e..90c7d6bb6 100644
--- a/app/components/Sidebar/components/SharedDocumentLink.tsx
+++ b/app/components/Sidebar/components/SharedDocumentLink.tsx
@@ -11,7 +11,8 @@ import SidebarLink from "./SidebarLink";
 type Props = {
   node: NavigationNode;
   collection?: Collection;
-  activeDocument: Document | null | undefined;
+  activeDocumentId: string | undefined;
+  activeDocument: Document | undefined;
   isDraft?: boolean;
   depth: number;
   index: number;
@@ -20,13 +21,21 @@ type Props = {
 };
 
 function DocumentLink(
-  { node, collection, activeDocument, isDraft, depth, shareId }: Props,
+  {
+    node,
+    collection,
+    activeDocument,
+    activeDocumentId,
+    isDraft,
+    depth,
+    shareId,
+  }: Props,
   ref: React.RefObject<HTMLAnchorElement>
 ) {
   const { documents } = useStores();
   const { t } = useTranslation();
 
-  const isActiveDocument = activeDocument && activeDocument.id === node.id;
+  const isActiveDocument = activeDocumentId === node.id;
 
   const hasChildDocuments =
     !!node.children.length || activeDocument?.parentDocumentId === node.id;
@@ -112,6 +121,7 @@ function DocumentLink(
             key={childNode.id}
             collection={collection}
             node={childNode}
+            activeDocumentId={activeDocumentId}
             activeDocument={activeDocument}
             isDraft={childNode.isDraft}
             depth={depth + 1}
diff --git a/app/scenes/Document/Shared.tsx b/app/scenes/Document/Shared.tsx
index 61bd6f25f..f09717bde 100644
--- a/app/scenes/Document/Shared.tsx
+++ b/app/scenes/Document/Shared.tsx
@@ -16,6 +16,11 @@ import Loading from "./components/Loading";
 
 const EMPTY_OBJECT = {};
 
+type Response = {
+  document: DocumentModel;
+  sharedTree?: NavigationNode | undefined;
+};
+
 type Props = RouteComponentProps<{
   shareId: string;
   documentSlug: string;
@@ -23,23 +28,58 @@ type Props = RouteComponentProps<{
   location: Location<{ title?: string }>;
 };
 
+/**
+ * Find the document UUID from the slug given the sharedTree
+ *
+ * @param documentSlug The slug from the url
+ * @param response The response payload from the server
+ * @returns The document UUID, if found.
+ */
+function useDocumentId(documentSlug: string, response?: Response) {
+  let documentId;
+
+  function findInTree(node: NavigationNode) {
+    if (node.url.endsWith(documentSlug)) {
+      documentId = node.id;
+      return true;
+    }
+    if (node.children) {
+      for (const child of node.children) {
+        if (findInTree(child)) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
+  if (response?.sharedTree) {
+    findInTree(response.sharedTree);
+  }
+
+  return documentId;
+}
+
 function SharedDocumentScene(props: Props) {
   const { ui } = useStores();
-
   const theme = useTheme();
-  const [response, setResponse] = React.useState<{
-    document: DocumentModel;
-    sharedTree?: NavigationNode | undefined;
-  }>();
+  const [response, setResponse] = React.useState<Response>();
   const [error, setError] = React.useState<Error | null | undefined>();
   const { documents } = useStores();
   const { shareId, documentSlug } = props.match.params;
+  const documentId = useDocumentId(documentSlug, response);
 
   // ensure the wider page color always matches the theme
   React.useEffect(() => {
     window.document.body.style.background = theme.background;
   }, [theme]);
 
+  React.useEffect(() => {
+    if (documentId) {
+      ui.setActiveDocument(documentId);
+    }
+  }, [ui, documentId]);
+
   React.useEffect(() => {
     async function fetchData() {
       try {
@@ -47,7 +87,6 @@ function SharedDocumentScene(props: Props) {
           shareId,
         });
         setResponse(response);
-        ui.setActiveDocument(response.document);
       } catch (err) {
         setError(err);
       }
diff --git a/app/stores/UiStore.ts b/app/stores/UiStore.ts
index 9cb3307a6..b93a7d86c 100644
--- a/app/stores/UiStore.ts
+++ b/app/stores/UiStore.ts
@@ -124,7 +124,13 @@ class UiStore {
   };
 
   @action
-  setActiveDocument = (document: Document): void => {
+  setActiveDocument = (document: Document | string): void => {
+    if (typeof document === "string") {
+      this.activeDocumentId = document;
+      this.observingUserId = undefined;
+      return;
+    }
+
     this.activeDocumentId = document.id;
     this.observingUserId = undefined;