Add note loading boundary (#2040)

* Remove redundant equal value

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Add NoteLoadingBoundary to fetch note from API before rendering

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Improve debug message for setHandler

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Add test for boundary

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Use common error page for note loading errors

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Fix tests

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Format code

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Add missing snapshot

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

* Reformat code

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

locales/en.json

@@ -40,6 +40,15 @@
       "uploadMessage": "Uploading file"
     }
   },
+  "noteLoadingBoundary": {
+    "errorWhileLoadingContent": "Error while loading note."
+  },
+  "api": {
+    "note": {
+      "notFound": "Note not found.",
+      "accessDenied": "You don't have the needed permission to access this note."
+    }
+  },
   "landing": {
     "intro": {
       "exploreFeatures": "Explore all features",

src/api/notes/index.ts

@@ -15,7 +15,9 @@ import { DeleteApiRequestBuilder } from '../common/api-request-builder/delete-ap
  * @return Content and metadata of the specified note.
  */
 export const getNote = async (noteIdOrAlias: string): Promise<Note> => {
-  const response = await new GetApiRequestBuilder<Note>('notes/' + noteIdOrAlias).sendRequest()
+  const response = await new GetApiRequestBuilder<Note>('notes/' + noteIdOrAlias)
+    .withStatusCodeErrorMapping({ 404: 'api.note.notFound', 403: 'api.note.accessDenied' })
+    .sendRequest()
   return response.asParsedJsonObject()
 }
 

src/components/application-loader/application-loader-error.ts

@@ -5,6 +5,6 @@
  */
 export class ApplicationLoaderError extends Error {
   constructor(taskName: string) {
-    super(`Task ${taskName} failed`)
+    super(`The task ${taskName} failed`)
   }
 }

src/components/application-loader/application-loader.tsx

@@ -5,7 +5,7 @@
  */
 
 import type { PropsWithChildren } from 'react'
-import React, { Suspense } from 'react'
+import React, { Fragment, Suspense, useMemo } from 'react'
 import { createSetUpTaskList } from './initializers'
 import { LoadingScreen } from './loading-screen/loading-screen'
 import { Logger } from '../../utils/logger'
@@ -27,8 +27,20 @@ export const ApplicationLoader: React.FC<PropsWithChildren<unknown>> = ({ childr
     }
   }, [])
 
-  if (loading) {
-    return <LoadingScreen failedTaskName={error?.message} />
+  const errorBlock = useMemo(() => {
+    if (error) {
+      return (
+        <Fragment>
+          {error.message}
+          <br />
+          For further information look into the browser console.
+        </Fragment>
+      )
+    }
+  }, [error])
+
+  if (loading || !!errorBlock) {
+    return <LoadingScreen errorMessage={errorBlock} />
   } else {
     return <Suspense fallback={<LoadingScreen />}>{children}</Suspense>
   }

src/components/application-loader/loading-screen/loading-screen.tsx

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+import type { ReactElement } from 'react'
 import React from 'react'
 import { Alert } from 'react-bootstrap'
 import { LoadingAnimation } from './loading-animation'
@@ -11,7 +12,7 @@ import { ShowIf } from '../../common/show-if/show-if'
 import styles from '../application-loader.module.scss'
 
 export interface LoadingScreenProps {
-  failedTaskName?: string
+  errorMessage?: string | ReactElement
 }
 
 /**
@@ -19,20 +20,16 @@ export interface LoadingScreenProps {
  *
  * @param failedTaskName Should be set if a task failed to load. The name will be shown on screen.
  */
-export const LoadingScreen: React.FC<LoadingScreenProps> = ({ failedTaskName }) => {
+export const LoadingScreen: React.FC<LoadingScreenProps> = ({ errorMessage }) => {
   return (
     <div className={`${styles.loader} ${styles.middle} text-light overflow-hidden`}>
       <div className='mb-3 text-light'>
         <span className={`d-block`}>
-          <LoadingAnimation error={!!failedTaskName} />
+          <LoadingAnimation error={!!errorMessage} />
         </span>
       </div>
-      <ShowIf condition={!!failedTaskName}>
-        <Alert variant={'danger'}>
-          The task {failedTaskName} failed.
-          <br />
-          For further information look into the browser console.
-        </Alert>
+      <ShowIf condition={!!errorMessage}>
+        <Alert variant={'danger'}>{errorMessage}</Alert>
       </ShowIf>
     </div>
   )

src/components/common/note-loading-boundary/__snapshots__/note-loading-boundary.test.tsx.snap

@@ -0,0 +1,32 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Note loading boundary loads a note 1`] = `
+<div>
+  <span
+    data-testid="success"
+  >
+    success!
+  </span>
+</div>
+`;
+
+exports[`Note loading boundary shows an error 1`] = `
+<div>
+  <span
+    data-testid="CommonErrorPage"
+  >
+    This is a mock for CommonErrorPage.
+  </span>
+  <span>
+    titleI18nKey: 
+    noteLoadingBoundary.errorWhileLoadingContent
+  </span>
+  <span>
+    descriptionI18nKey: 
+    CRAAAAASH
+  </span>
+  <span>
+    children: 
+  </span>
+</div>
+`;

src/components/common/note-loading-boundary/hooks/use-load-note-from-server.ts

@@ -0,0 +1,28 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { useAsync } from 'react-use'
+import { getNote } from '../../../../api/notes'
+import { setNoteDataFromServer } from '../../../../redux/note-details/methods'
+import { useSingleStringUrlParameter } from '../../../../hooks/common/use-single-string-url-parameter'
+import type { AsyncState } from 'react-use/lib/useAsyncFn'
+
+/**
+ * Reads the note id from the current URL, requests the note from the backend and writes it into the global application state.
+ *
+ * @return An {@link AsyncState async state} that represents the current state of the loading process.
+ */
+export const useLoadNoteFromServer = (): AsyncState<void> => {
+  const id = useSingleStringUrlParameter('noteId', undefined)
+
+  return useAsync(async () => {
+    if (id === undefined) {
+      throw new Error('Invalid id')
+    }
+    const noteFromServer = await getNote(id)
+    setNoteDataFromServer(noteFromServer)
+  }, [id])
+}

src/components/common/note-loading-boundary/note-loading-boundary.test.tsx

@@ -0,0 +1,115 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import * as useSingleStringUrlParameterModule from '../../../hooks/common/use-single-string-url-parameter'
+import * as getNoteModule from '../../../api/notes'
+import * as setNoteDataFromServerModule from '../../../redux/note-details/methods'
+import type { Note } from '../../../api/notes/types'
+import { Mock } from 'ts-mockery'
+import { render, screen } from '@testing-library/react'
+import { NoteLoadingBoundary } from './note-loading-boundary'
+import { testId } from '../../../utils/test-id'
+import { Fragment } from 'react'
+import { mockI18n } from '../../markdown-renderer/test-utils/mock-i18n'
+import * as CommonErrorPageModule from '../../error-pages/common-error-page'
+import * as LoadingScreenModule from '../../../components/application-loader/loading-screen/loading-screen'
+
+describe('Note loading boundary', () => {
+  const mockedNoteId = 'mockedNoteId'
+
+  afterEach(() => {
+    jest.resetAllMocks()
+    jest.resetModules()
+  })
+
+  beforeEach(async () => {
+    await mockI18n()
+    jest.spyOn(LoadingScreenModule, 'LoadingScreen').mockImplementation(({ errorMessage }) => {
+      return (
+        <Fragment>
+          <span {...testId('LoadingScreen')}>This is a mock for LoadingScreen.</span>
+          <span>errorMessage: {errorMessage}</span>
+        </Fragment>
+      )
+    })
+    jest
+      .spyOn(CommonErrorPageModule, 'CommonErrorPage')
+      .mockImplementation(({ titleI18nKey, descriptionI18nKey, children }) => {
+        return (
+          <Fragment>
+            <span {...testId('CommonErrorPage')}>This is a mock for CommonErrorPage.</span>
+            <span>titleI18nKey: {titleI18nKey}</span>
+            <span>descriptionI18nKey: {descriptionI18nKey}</span>
+            <span>children: {children}</span>
+          </Fragment>
+        )
+      })
+    mockGetNoteIdQueryParameter()
+  })
+
+  const mockGetNoteIdQueryParameter = () => {
+    const expectedQueryParameter = 'noteId'
+    jest.spyOn(useSingleStringUrlParameterModule, 'useSingleStringUrlParameter').mockImplementation((parameter) => {
+      expect(parameter).toBe(expectedQueryParameter)
+      return mockedNoteId
+    })
+  }
+
+  const mockGetNoteApiCall = (returnValue: Note) => {
+    jest.spyOn(getNoteModule, 'getNote').mockImplementation((id) => {
+      expect(id).toBe(mockedNoteId)
+      return new Promise((resolve) => {
+        setTimeout(() => resolve(returnValue), 0)
+      })
+    })
+  }
+
+  const mockCrashingNoteApiCall = () => {
+    jest.spyOn(getNoteModule, 'getNote').mockImplementation((id) => {
+      expect(id).toBe(mockedNoteId)
+      return new Promise((resolve, reject) => {
+        setTimeout(() => reject(new Error('CRAAAAASH')), 0)
+      })
+    })
+  }
+
+  const mockSetNoteInRedux = (expectedNote: Note): jest.SpyInstance<void, [apiResponse: Note]> => {
+    return jest.spyOn(setNoteDataFromServerModule, 'setNoteDataFromServer').mockImplementation((givenNote) => {
+      expect(givenNote).toBe(expectedNote)
+    })
+  }
+
+  it('loads a note', async () => {
+    const mockedNote: Note = Mock.of<Note>()
+    mockGetNoteApiCall(mockedNote)
+    const setNoteInReduxFunctionMock = mockSetNoteInRedux(mockedNote)
+
+    const view = render(
+      <NoteLoadingBoundary>
+        <span data-testid={'success'}>success!</span>
+      </NoteLoadingBoundary>
+    )
+    await screen.findByTestId('LoadingScreen')
+    await screen.findByTestId('success')
+    expect(view.container).toMatchSnapshot()
+    expect(setNoteInReduxFunctionMock).toBeCalledWith(mockedNote)
+  })
+
+  it('shows an error', async () => {
+    const mockedNote: Note = Mock.of<Note>()
+    mockCrashingNoteApiCall()
+    const setNoteInReduxFunctionMock = mockSetNoteInRedux(mockedNote)
+
+    const view = render(
+      <NoteLoadingBoundary>
+        <span data-testid={'success'}>success!</span>
+      </NoteLoadingBoundary>
+    )
+    await screen.findByTestId('LoadingScreen')
+    await screen.findByTestId('CommonErrorPage')
+    expect(view.container).toMatchSnapshot()
+    expect(setNoteInReduxFunctionMock).not.toBeCalled()
+  })
+})

src/components/common/note-loading-boundary/note-loading-boundary.tsx

@@ -0,0 +1,35 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { PropsWithChildren } from 'react'
+import React, { Fragment } from 'react'
+import { useLoadNoteFromServer } from './hooks/use-load-note-from-server'
+import { LoadingScreen } from '../../application-loader/loading-screen/loading-screen'
+import { CommonErrorPage } from '../../error-pages/common-error-page'
+
+/**
+ * Loads the note identified by the note-id in the URL.
+ * During the loading a {@link LoadingScreen loading screen} will be rendered instead of the child elements.
+ * The boundary also shows errors that occur during the loading process.
+ *
+ * @param children The react elements that will be shown when the loading was successful.
+ */
+export const NoteLoadingBoundary: React.FC<PropsWithChildren<unknown>> = ({ children }) => {
+  const { error, loading } = useLoadNoteFromServer()
+
+  if (loading) {
+    return <LoadingScreen />
+  } else if (error) {
+    return (
+      <CommonErrorPage
+        titleI18nKey={'noteLoadingBoundary.errorWhileLoadingContent'}
+        descriptionI18nKey={error.message}
+      />
+    )
+  } else {
+    return <Fragment>{children}</Fragment>
+  }
+}

src/components/document-read-only-page/ErrorWhileLoadingNoteAlert.tsx

@@ -1,27 +0,0 @@
-/*
- * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
- *
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-import React from 'react'
-import { Alert } from 'react-bootstrap'
-import { Trans, useTranslation } from 'react-i18next'
-import { ShowIf } from '../common/show-if/show-if'
-import type { SimpleAlertProps } from '../common/simple-alert/simple-alert-props'
-
-export const ErrorWhileLoadingNoteAlert: React.FC<SimpleAlertProps> = ({ show }) => {
-  useTranslation()
-
-  return (
-    <ShowIf condition={show}>
-      <Alert variant={'danger'} className={'my-2'}>
-        <b>
-          <Trans i18nKey={'views.readOnly.error.title'} />
-        </b>
-        <br />
-        <Trans i18nKey={'views.readOnly.error.description'} />
-      </Alert>
-    </ShowIf>
-  )
-}

src/components/document-read-only-page/LoadingNoteAlert.tsx

@@ -1,21 +0,0 @@
-/*
- * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
- *
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-import React from 'react'
-import { Alert } from 'react-bootstrap'
-import { Trans } from 'react-i18next'
-import { ShowIf } from '../common/show-if/show-if'
-import type { SimpleAlertProps } from '../common/simple-alert/simple-alert-props'
-
-export const LoadingNoteAlert: React.FC<SimpleAlertProps> = ({ show }) => {
-  return (
-    <ShowIf condition={show}>
-      <Alert variant={'info'} className={'my-2'}>
-        <Trans i18nKey={'views.readOnly.loading'} />
-      </Alert>
-    </ShowIf>
-  )
-}

src/components/editor-page/editor-page-content.tsx

@@ -9,12 +9,8 @@ import { useTranslation } from 'react-i18next'
 import { useApplyDarkMode } from '../../hooks/common/use-apply-dark-mode'
 import { setCheckboxInMarkdownContent, updateNoteTitleByFirstHeading } from '../../redux/note-details/methods'
 import { MotdModal } from '../common/motd-modal/motd-modal'
-import { ShowIf } from '../common/show-if/show-if'
-import { ErrorWhileLoadingNoteAlert } from '../document-read-only-page/ErrorWhileLoadingNoteAlert'
-import { LoadingNoteAlert } from '../document-read-only-page/LoadingNoteAlert'
 import { AppBar, AppBarMode } from './app-bar/app-bar'
 import { EditorMode } from './app-bar/editor-view-mode'
-import { useLoadNoteFromServer } from './hooks/useLoadNoteFromServer'
 import { useViewModeShortcuts } from './hooks/useViewModeShortcuts'
 import { Sidebar } from './sidebar/sidebar'
 import { Splitter } from './splitter/splitter'
@@ -31,10 +27,6 @@ import { NoteAndAppTitleHead } from '../layout/note-and-app-title-head'
 import equal from 'fast-deep-equal'
 import { EditorPane } from './editor-pane/editor-pane'
 
-export interface EditorPagePathParams {
-  id: string
-}
-
 export enum ScrollSource {
   EDITOR = 'editor',
   RENDERER = 'renderer'
@@ -94,9 +86,7 @@ export const EditorPageContent: React.FC = () => {
   useApplyDarkMode()
   useEditorModeFromUrl()
 
-  const [error, loading] = useLoadNoteFromServer()
-
-  useUpdateLocalHistoryEntry(!error && !loading)
+  useUpdateLocalHistoryEntry()
 
   const setRendererToScrollSource = useCallback(() => {
     if (scrollSource.current !== ScrollSource.RENDERER) {
@@ -146,22 +136,16 @@ export const EditorPageContent: React.FC = () => {
       <MotdModal />
       <div className={'d-flex flex-column vh-100'}>
         <AppBar mode={AppBarMode.EDITOR} />
-        <div className={'container'}>
-          <ErrorWhileLoadingNoteAlert show={error} />
-          <LoadingNoteAlert show={loading} />
+        <div className={'flex-fill d-flex h-100 w-100 overflow-hidden flex-row'}>
+          <Splitter
+            showLeft={editorMode === EditorMode.EDITOR || editorMode === EditorMode.BOTH}
+            left={leftPane}
+            showRight={editorMode === EditorMode.PREVIEW || editorMode === EditorMode.BOTH}
+            right={rightPane}
+            additionalContainerClassName={'overflow-hidden'}
+          />
+          <Sidebar />
         </div>
-        <ShowIf condition={!error && !loading}>
-          <div className={'flex-fill d-flex h-100 w-100 overflow-hidden flex-row'}>
-            <Splitter
-              showLeft={editorMode === EditorMode.EDITOR || editorMode === EditorMode.BOTH}
-              left={leftPane}
-              showRight={editorMode === EditorMode.PREVIEW || editorMode === EditorMode.BOTH}
-              right={rightPane}
-              additionalContainerClassName={'overflow-hidden'}
-            />
-            <Sidebar />
-          </div>
-        </ShowIf>
       </div>
     </Fragment>
   )

src/components/editor-page/hooks/useLoadNoteFromServer.ts

@@ -1,36 +0,0 @@
-/*
- * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
- *
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-import { getNote } from '../../../api/notes'
-import { setNoteDataFromServer } from '../../../redux/note-details/methods'
-import { Logger } from '../../../utils/logger'
-import { useRouter } from 'next/router'
-import { useAsync } from 'react-use'
-
-const log = new Logger('Load Note From Server')
-
-export const useLoadNoteFromServer = (): [boolean, boolean] => {
-  const { query } = useRouter()
-
-  const { loading, error } = useAsync(() => {
-    const rawId = query.id
-    if (rawId === undefined) {
-      return Promise.reject('invalid id')
-    }
-    const id = typeof rawId === 'string' ? rawId : rawId[0]
-
-    return getNote(id)
-      .then((note) => {
-        setNoteDataFromServer(note)
-      })
-      .catch((error: Error) => {
-        log.error('Error while fetching note from server', error)
-        return Promise.reject(error)
-      })
-  }, [query])
-
-  return [error !== undefined, loading]
-}

src/components/editor-page/hooks/useUpdateLocalHistoryEntry.ts

@@ -12,7 +12,7 @@ import { useApplicationState } from '../../../hooks/common/use-application-state
 import type { HistoryEntryWithOrigin } from '../../../api/history/types'
 import { HistoryEntryOrigin } from '../../../api/history/types'
 
-export const useUpdateLocalHistoryEntry = (updateReady: boolean): void => {
+export const useUpdateLocalHistoryEntry = (): void => {
   const id = useApplicationState((state) => state.noteDetails.id)
   const userExists = useApplicationState((state) => !!state.user)
   const currentNoteTitle = useApplicationState((state) => state.noteDetails.title)
@@ -22,7 +22,7 @@ export const useUpdateLocalHistoryEntry = (updateReady: boolean): void => {
   const lastNoteTags = useRef<string[]>([])
 
   useEffect(() => {
-    if (!updateReady || userExists) {
+    if (userExists) {
       return
     }
     if (currentNoteTitle === lastNoteTitle.current && equal(currentNoteTags, lastNoteTags.current)) {
@@ -46,5 +46,5 @@ export const useUpdateLocalHistoryEntry = (updateReady: boolean): void => {
     updateLocalHistoryEntry(id, entry)
     lastNoteTitle.current = currentNoteTitle
     lastNoteTags.current = currentNoteTags
-  }, [updateReady, id, userExists, currentNoteTitle, currentNoteTags])
+  }, [id, userExists, currentNoteTitle, currentNoteTags])
 }

src/components/render-page/window-post-message-communicator/window-post-message-communicator.ts

@@ -120,7 +120,7 @@ export abstract class WindowPostMessageCommunicator<
    * @param handler The handler that processes messages with the given message type.
    */
   public setHandler<R extends RECEIVE_TYPE>(messageType: R, handler: MaybeHandler<MESSAGES, R>): void {
-    this.log.debug('Set handler for', messageType)
+    this.log.debug(handler === undefined ? 'Unset' : 'Set', 'handler for', messageType)
     this.handlers[messageType] = handler as MaybeHandler<MESSAGES, RECEIVE_TYPE>
   }
 

src/hooks/common/use-trimmed-note-markdown-content-without-frontmatter.ts

@@ -6,20 +6,16 @@
 
 import { useMemo } from 'react'
 import { useApplicationState } from './use-application-state'
-import equal from 'fast-deep-equal'
 
 /**
  * Returns the markdown content from the global application state trimmed to the maximal note length and without the frontmatter lines.
  */
 export const useTrimmedNoteMarkdownContentWithoutFrontmatter = (): string[] => {
   const maxLength = useApplicationState((state) => state.config.maxDocumentLength)
-  const markdownContent = useApplicationState(
-    (state) => ({
-      lines: state.noteDetails.markdownContent.lines,
-      content: state.noteDetails.markdownContent.plain
-    }),
-    equal
-  )
+  const markdownContent = useApplicationState((state) => ({
+    lines: state.noteDetails.markdownContent.lines,
+    content: state.noteDetails.markdownContent.plain
+  }))
   const lineOffset = useApplicationState((state) => state.noteDetails.frontmatterRendererInfo.lineOffset)
 
   const trimmedLines = useMemo(() => {

src/pages/n/[noteId].tsx

@@ -8,15 +8,18 @@ import React from 'react'
 import { EditorToRendererCommunicatorContextProvider } from '../../components/editor-page/render-context/editor-to-renderer-communicator-context-provider'
 import type { NextPage } from 'next'
 import { EditorPageContent } from '../../components/editor-page/editor-page-content'
+import { NoteLoadingBoundary } from '../../components/common/note-loading-boundary/note-loading-boundary'
 
 /**
  * Renders a page that is used by the user to edit markdown notes. It contains the editor and a renderer.
  */
 export const EditorPage: NextPage = () => {
   return (
-    <EditorToRendererCommunicatorContextProvider>
-      <EditorPageContent />
-    </EditorToRendererCommunicatorContextProvider>
+    <NoteLoadingBoundary>
+      <EditorToRendererCommunicatorContextProvider>
+        <EditorPageContent />
+      </EditorToRendererCommunicatorContextProvider>
+    </NoteLoadingBoundary>
   )
 }
 

src/pages/p/[noteId].tsx

@@ -4,25 +4,20 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import React, { Fragment } from 'react'
-import { useLoadNoteFromServer } from '../../components/editor-page/hooks/useLoadNoteFromServer'
-import { ShowIf } from '../../components/common/show-if/show-if'
+import React from 'react'
 import { EditorToRendererCommunicatorContextProvider } from '../../components/editor-page/render-context/editor-to-renderer-communicator-context-provider'
 import { SlideShowPageContent } from '../../components/slide-show-page/slide-show-page-content'
 import { NoteAndAppTitleHead } from '../../components/layout/note-and-app-title-head'
+import { NoteLoadingBoundary } from '../../components/common/note-loading-boundary/note-loading-boundary'
 
 export const SlideShowPage: React.FC = () => {
-  const [error, loading] = useLoadNoteFromServer()
-
   return (
-    <Fragment>
+    <NoteLoadingBoundary>
       <NoteAndAppTitleHead />
       <EditorToRendererCommunicatorContextProvider>
-        <ShowIf condition={!error && !loading}>
-          <SlideShowPageContent />
-        </ShowIf>
+        <SlideShowPageContent />
       </EditorToRendererCommunicatorContextProvider>
-    </Fragment>
+    </NoteLoadingBoundary>
   )
 }
 

src/pages/s/[noteId].tsx

@@ -7,37 +7,29 @@
 import React from 'react'
 import { useApplyDarkMode } from '../../hooks/common/use-apply-dark-mode'
 import { MotdModal } from '../../components/common/motd-modal/motd-modal'
-import { ShowIf } from '../../components/common/show-if/show-if'
 import { AppBar, AppBarMode } from '../../components/editor-page/app-bar/app-bar'
-import { useLoadNoteFromServer } from '../../components/editor-page/hooks/useLoadNoteFromServer'
-import { ErrorWhileLoadingNoteAlert } from '../../components/document-read-only-page/ErrorWhileLoadingNoteAlert'
-import { LoadingNoteAlert } from '../../components/document-read-only-page/LoadingNoteAlert'
 import { EditorToRendererCommunicatorContextProvider } from '../../components/editor-page/render-context/editor-to-renderer-communicator-context-provider'
 import { UiNotifications } from '../../components/notifications/ui-notifications'
 import { DocumentReadOnlyPageContent } from '../../components/document-read-only-page/document-read-only-page-content'
 import { NoteAndAppTitleHead } from '../../components/layout/note-and-app-title-head'
+import { NoteLoadingBoundary } from '../../components/common/note-loading-boundary/note-loading-boundary'
 
 /**
  * Renders a page that contains only the rendered document without an editor or realtime updates.
  */
 export const DocumentReadOnlyPage: React.FC = () => {
   useApplyDarkMode()
-  const [error, loading] = useLoadNoteFromServer()
   return (
     <EditorToRendererCommunicatorContextProvider>
-      <NoteAndAppTitleHead />
-      <UiNotifications />
-      <MotdModal />
-      <div className={'d-flex flex-column mvh-100 bg-light'}>
-        <AppBar mode={AppBarMode.BASIC} />
-        <div className={'container'}>
-          <ErrorWhileLoadingNoteAlert show={error} />
-          <LoadingNoteAlert show={loading} />
-        </div>
-        <ShowIf condition={!error && !loading}>
+      <NoteLoadingBoundary>
+        <NoteAndAppTitleHead />
+        <UiNotifications />
+        <MotdModal />
+        <div className={'d-flex flex-column mvh-100 bg-light'}>
+          <AppBar mode={AppBarMode.BASIC} />
           <DocumentReadOnlyPageContent />
-        </ShowIf>
-      </div>
+        </div>
+      </NoteLoadingBoundary>
     </EditorToRendererCommunicatorContextProvider>
   )
 }