From a16cf72b73c9f091ce738fb2f3bb9234a1fe8c9d Mon Sep 17 00:00:00 2001
From: Tom Moor <tom.moor@gmail.com>
Date: Sat, 16 Jul 2022 00:11:04 +0100
Subject: [PATCH] feat: Error state for paginated lists (#3766)

* Add error state for failed list loading

* Move sidebar collections to PaginatedList for improved error handling, loading, retrying etc
---
 app/components/ButtonLink.tsx                 |  13 +-
 app/components/Empty.ts                       |   1 +
 app/components/List/Error.tsx                 |  53 ++++++++
 app/components/PaginatedDocumentList.tsx      |   2 +
 app/components/PaginatedList.tsx              |  52 +++++---
 .../Sidebar/components/Collections.tsx        | 115 ++++++++----------
 shared/i18n/locales/en_US/translation.json    |   5 +-
 7 files changed, 148 insertions(+), 93 deletions(-)
 create mode 100644 app/components/List/Error.tsx

diff --git a/app/components/ButtonLink.tsx b/app/components/ButtonLink.tsx
index 4d3463928..1bb65ac62 100644
--- a/app/components/ButtonLink.tsx
+++ b/app/components/ButtonLink.tsx
@@ -1,17 +1,6 @@
-import * as React from "react";
 import styled from "styled-components";
 
-type Props = {
-  onClick?: React.MouseEventHandler<HTMLButtonElement>;
-};
-
-const ButtonLink: React.FC<Props> = React.forwardRef(
-  (props: Props, ref: React.Ref<HTMLButtonElement>) => {
-    return <Button {...props} ref={ref} />;
-  }
-);
-
-const Button = styled.button`
+const ButtonLink = styled.button`
   margin: 0;
   padding: 0;
   border: 0;
diff --git a/app/components/Empty.ts b/app/components/Empty.ts
index 3e294fe3c..db9550f30 100644
--- a/app/components/Empty.ts
+++ b/app/components/Empty.ts
@@ -2,6 +2,7 @@ import styled from "styled-components";
 
 const Empty = styled.p`
   color: ${(props) => props.theme.textTertiary};
+  user-select: none;
 `;
 
 export default Empty;
diff --git a/app/components/List/Error.tsx b/app/components/List/Error.tsx
new file mode 100644
index 000000000..ca0fb58eb
--- /dev/null
+++ b/app/components/List/Error.tsx
@@ -0,0 +1,53 @@
+import { DisconnectedIcon, WarningIcon } from "outline-icons";
+import * as React from "react";
+import { useTranslation } from "react-i18next";
+import styled from "styled-components";
+import Empty from "~/components/Empty";
+import useEventListener from "~/hooks/useEventListener";
+import { OfflineError } from "~/utils/errors";
+import ButtonLink from "../ButtonLink";
+import Flex from "../Flex";
+
+type Props = {
+  error: Error;
+  retry: () => void;
+};
+
+export default function LoadingError({ error, retry, ...rest }: Props) {
+  const { t } = useTranslation();
+  useEventListener("online", retry);
+
+  const message =
+    error instanceof OfflineError ? (
+      <>
+        <DisconnectedIcon color="currentColor" /> {t("You’re offline.")}
+      </>
+    ) : (
+      <>
+        <WarningIcon color="currentColor" /> {t("Sorry, an error occurred.")}
+      </>
+    );
+
+  return (
+    <Content {...rest}>
+      <Flex align="center" gap={4}>
+        {message}{" "}
+        <ButtonLink onClick={() => retry()}>{t("Click to retry")}…</ButtonLink>
+      </Flex>
+    </Content>
+  );
+}
+
+const Content = styled(Empty)`
+  padding: 8px 0;
+  white-space: nowrap;
+
+  ${ButtonLink} {
+    color: ${(props) => props.theme.textTertiary};
+
+    &:hover {
+      color: ${(props) => props.theme.textSecondary};
+      text-decoration: underline;
+    }
+  }
+`;
diff --git a/app/components/PaginatedDocumentList.tsx b/app/components/PaginatedDocumentList.tsx
index c0eeb07d3..1b93c5bb1 100644
--- a/app/components/PaginatedDocumentList.tsx
+++ b/app/components/PaginatedDocumentList.tsx
@@ -2,6 +2,7 @@ import * as React from "react";
 import { useTranslation } from "react-i18next";
 import Document from "~/models/Document";
 import DocumentListItem from "~/components/DocumentListItem";
+import Error from "~/components/List/Error";
 import PaginatedList from "~/components/PaginatedList";
 
 type Props = {
@@ -40,6 +41,7 @@ const PaginatedDocumentList = React.memo<Props>(function PaginatedDocumentList({
       heading={heading}
       fetch={fetch}
       options={options}
+      renderError={(props) => <Error {...props} />}
       renderItem={(item: Document, _index, compositeProps) => (
         <DocumentListItem
           key={item.id}
diff --git a/app/components/PaginatedList.tsx b/app/components/PaginatedList.tsx
index 0ab5bf264..e50250f9b 100644
--- a/app/components/PaginatedList.tsx
+++ b/app/components/PaginatedList.tsx
@@ -34,12 +34,19 @@ type Props<T> = WithTranslation &
       index: number,
       compositeProps: CompositeStateReturn
     ) => React.ReactNode;
+    renderError?: (options: {
+      error: Error;
+      retry: () => void;
+    }) => React.ReactNode;
     renderHeading?: (name: React.ReactElement<any> | string) => React.ReactNode;
     onEscape?: (ev: React.KeyboardEvent<HTMLDivElement>) => void;
   };
 
 @observer
 class PaginatedList<T extends PaginatedItem> extends React.Component<Props<T>> {
+  @observable
+  error?: Error;
+
   @observable
   isFetchingMore = false;
 
@@ -80,6 +87,7 @@ class PaginatedList<T extends PaginatedItem> extends React.Component<Props<T>> {
     this.isFetchingMore = false;
   };
 
+  @action
   fetchResults = async () => {
     if (!this.props.fetch) {
       return;
@@ -87,25 +95,30 @@ class PaginatedList<T extends PaginatedItem> extends React.Component<Props<T>> {
     this.isFetching = true;
     const counter = ++this.fetchCounter;
     const limit = DEFAULT_PAGINATION_LIMIT;
+    this.error = undefined;
 
-    const results = await this.props.fetch({
-      limit,
-      offset: this.offset,
-      ...this.props.options,
-    });
+    try {
+      const results = await this.props.fetch({
+        limit,
+        offset: this.offset,
+        ...this.props.options,
+      });
 
-    if (results && (results.length === 0 || results.length < limit)) {
-      this.allowLoadMore = false;
-    } else {
-      this.offset += limit;
-    }
+      if (results && (results.length === 0 || results.length < limit)) {
+        this.allowLoadMore = false;
+      } else {
+        this.offset += limit;
+      }
 
-    this.renderCount += limit;
-
-    // only the most recent fetch should end the loading state
-    if (counter >= this.fetchCounter) {
-      this.isFetching = false;
-      this.isFetchingMore = false;
+      this.renderCount += limit;
+    } catch (err) {
+      this.error = err;
+    } finally {
+      // only the most recent fetch should end the loading state
+      if (counter >= this.fetchCounter) {
+        this.isFetching = false;
+        this.isFetchingMore = false;
+      }
     }
   };
 
@@ -138,7 +151,9 @@ class PaginatedList<T extends PaginatedItem> extends React.Component<Props<T>> {
       auth,
       empty = null,
       renderHeading,
+      renderError,
       onEscape,
+      children,
     } = this.props;
 
     const showLoading =
@@ -157,6 +172,10 @@ class PaginatedList<T extends PaginatedItem> extends React.Component<Props<T>> {
     }
 
     if (items?.length === 0) {
+      if (this.error && renderError) {
+        return renderError({ error: this.error, retry: this.fetchResults });
+      }
+
       return empty;
     }
 
@@ -205,6 +224,7 @@ class PaginatedList<T extends PaginatedItem> extends React.Component<Props<T>> {
             });
           }}
         </ArrowKeyNavigation>
+        {children}
         {this.allowLoadMore && (
           <Waypoint key={this.renderCount} onEnter={this.loadMoreResults} />
         )}
diff --git a/app/components/Sidebar/components/Collections.tsx b/app/components/Sidebar/components/Collections.tsx
index c559993f0..ac03c0618 100644
--- a/app/components/Sidebar/components/Collections.tsx
+++ b/app/components/Sidebar/components/Collections.tsx
@@ -3,12 +3,14 @@ import { observer } from "mobx-react";
 import * as React from "react";
 import { useDrop } from "react-dnd";
 import { useTranslation } from "react-i18next";
+import styled from "styled-components";
 import Collection from "~/models/Collection";
-import Fade from "~/components/Fade";
 import Flex from "~/components/Flex";
+import Error from "~/components/List/Error";
+import PaginatedList from "~/components/PaginatedList";
+import Text from "~/components/Text";
 import { createCollection } from "~/actions/definitions/collections";
 import useStores from "~/hooks/useStores";
-import useToasts from "~/hooks/useToasts";
 import DraggableCollectionLink from "./DraggableCollectionLink";
 import DropCursor from "./DropCursor";
 import Header from "./Header";
@@ -18,39 +20,10 @@ import SidebarAction from "./SidebarAction";
 import { DragObject } from "./SidebarLink";
 
 function Collections() {
-  const [isFetching, setFetching] = React.useState(false);
-  const [fetchError, setFetchError] = React.useState();
   const { documents, collections } = useStores();
-  const { showToast } = useToasts();
-  const isPreloaded = !!collections.orderedData.length;
   const { t } = useTranslation();
   const orderedCollections = collections.orderedData;
 
-  React.useEffect(() => {
-    async function load() {
-      if (!collections.isLoaded && !isFetching && !fetchError) {
-        try {
-          setFetching(true);
-          await collections.fetchPage({
-            limit: 100,
-          });
-        } catch (error) {
-          showToast(
-            t("Collections could not be loaded, please reload the app"),
-            {
-              type: "error",
-            }
-          );
-          setFetchError(error);
-        } finally {
-          setFetching(false);
-        }
-      }
-    }
-
-    load();
-  }, [collections, isFetching, showToast, fetchError, t]);
-
   const [
     { isCollectionDropping, isDraggingAnyCollection },
     dropToReorderCollection,
@@ -71,45 +44,59 @@ function Collections() {
     }),
   });
 
-  const content = (
-    <>
-      {isDraggingAnyCollection && (
-        <DropCursor
-          isActiveDrop={isCollectionDropping}
-          innerRef={dropToReorderCollection}
-          position="top"
-        />
-      )}
-      {orderedCollections.map((collection: Collection, index: number) => (
-        <DraggableCollectionLink
-          key={collection.id}
-          collection={collection}
-          activeDocument={documents.active}
-          prefetchDocument={documents.prefetchDocument}
-          belowCollection={orderedCollections[index + 1]}
-        />
-      ))}
-      <SidebarAction action={createCollection} depth={0} />
-    </>
-  );
-
-  if (!collections.isLoaded || fetchError) {
-    return (
-      <Flex column>
-        <Header id="collections" title={t("Collections")}>
-          <PlaceholderCollections />
-        </Header>
-      </Flex>
-    );
-  }
-
   return (
     <Flex column>
       <Header id="collections" title={t("Collections")}>
-        <Relative>{isPreloaded ? content : <Fade>{content}</Fade>}</Relative>
+        <Relative>
+          <PaginatedList
+            aria-label={t("Collections")}
+            items={collections.orderedData}
+            fetch={collections.fetchPage}
+            options={{ limit: 100 }}
+            loading={<PlaceholderCollections />}
+            heading={
+              isDraggingAnyCollection ? (
+                <DropCursor
+                  isActiveDrop={isCollectionDropping}
+                  innerRef={dropToReorderCollection}
+                  position="top"
+                />
+              ) : undefined
+            }
+            empty={
+              <Empty type="tertiary" size="small">
+                {t("Empty")}
+              </Empty>
+            }
+            renderError={(props) => <StyledError {...props} />}
+            renderItem={(item: Collection, index) => (
+              <DraggableCollectionLink
+                key={item.id}
+                collection={item}
+                activeDocument={documents.active}
+                prefetchDocument={documents.prefetchDocument}
+                belowCollection={orderedCollections[index + 1]}
+              />
+            )}
+          >
+            <SidebarAction action={createCollection} depth={0} />
+          </PaginatedList>
+        </Relative>
       </Header>
     </Flex>
   );
 }
 
+const Empty = styled(Text)`
+  margin-left: 36px;
+  margin-bottom: 0;
+  line-height: 34px;
+  font-style: italic;
+`;
+
+const StyledError = styled(Error)`
+  font-size: 15px;
+  padding: 0 8px;
+`;
+
 export default observer(Collections);
diff --git a/shared/i18n/locales/en_US/translation.json b/shared/i18n/locales/en_US/translation.json
index ccc814e4a..f9e9b6711 100644
--- a/shared/i18n/locales/en_US/translation.json
+++ b/shared/i18n/locales/en_US/translation.json
@@ -148,6 +148,9 @@
   "Outline is available in your language {{optionLabel}}, would you like to change?": "Outline is available in your language {{optionLabel}}, would you like to change?",
   "Change Language": "Change Language",
   "Dismiss": "Dismiss",
+  "You’re offline.": "You’re offline.",
+  "Sorry, an error occurred.": "Sorry, an error occurred.",
+  "Click to retry": "Click to retry",
   "Back": "Back",
   "Documents": "Documents",
   "Results": "Results",
@@ -157,10 +160,10 @@
   "Move document": "Move document",
   "You can't reorder documents in an alphabetically sorted collection": "You can't reorder documents in an alphabetically sorted collection",
   "Collections": "Collections",
+  "Empty": "Empty",
   "Untitled": "Untitled",
   "New nested document": "New nested document",
   "Document not supported – try Markdown, Plain text, HTML, or Word": "Document not supported – try Markdown, Plain text, HTML, or Word",
-  "Empty": "Empty",
   "Starred documents could not be loaded": "Starred documents could not be loaded",
   "Starred": "Starred",
   "Show more": "Show more",