Add offline support to <ReferenceManyFieldBase> and <ReferenceManyField>

docs/ReferenceManyField.md

@@ -96,6 +96,7 @@ This example leverages [`<SingleFieldList>`](./SingleFieldList.md) to display an
 | `debounce`     | Optional | `number`                                                                          | 500                              | debounce time in ms for the `setFilters` callbacks                                  |
 | `empty`        | Optional | `ReactNode`                                                                       | -                                | Element to display when there are no related records.                                |
 | `filter`       | Optional | `Object`                                                                          | -                                | Filters to use when fetching the related records, passed to `getManyReference()`    |
+| `offline`      | Optional | `ReactNode`                                                                       | -                                | Element to display when there are no related records because of lack of network connectivity. |
 | `pagination`   | Optional | `Element`                                                                         | -                                | Pagination element to display pagination controls. empty by default (no pagination) |
 | `perPage`      | Optional | `number`                                                                          | 25                               | Maximum number of referenced records to fetch                                       |
 | `queryOptions` | Optional | [`UseQuery Options`](https://tanstack.com/query/v3/docs/react/reference/useQuery) | `{}`                             | `react-query` options for the `getMany` query                                       |
@@ -307,6 +308,49 @@ React-admin uses [the i18n system](./Translation.md) to translate the label, so
 </ReferenceManyField>
 ```
 
+## `offline`
+
+By default, `<ReferenceManyField>` renders the `<Offline variant="inline">` when there is no connectivity and the records haven't been cached yet. You can provide your own component via the `offline` prop:
+
+```jsx
+<ReferenceManyField
+    reference="books"
+    target="author_id"
+    offline="Offline, could not load data"
+>
+    ...
+</ReferenceManyField>
+```
+
+`offline` also accepts a `ReactNode`.
+
+```jsx
+<ReferenceManyField
+    reference="books"
+    target="author_id"
+    empty={<Alert severity="warning">Offline, could not load data</Alert>}
+>
+    ...
+</ReferenceManyField>
+```
+
+**Tip**: If the records are in the Tanstack Query cache but you want to warn the user that they may see an outdated version, you can use the `<IsOffline>` component:
+
+```jsx
+<ReferenceManyField
+    reference="books"
+    target="author_id"
+    empty={<Alert severity="warning">Offline, could not load data</Alert>}
+>
+  <IsOffline>
+      <Alert severity="warning">
+          You are offline, the data may be outdated
+      </Alert>
+  </IsOffline>
+    ...
+</ReferenceManyField>
+```
+
 ## `pagination`
 
 If you want to allow users to paginate the list, pass a `<Pagination>` element as the `pagination` prop:

packages/ra-core/src/controller/field/ReferenceManyFieldBase.tsx

@@ -113,14 +113,20 @@ export const ReferenceManyFieldBase = <
         hasPreviousPage,
         isPaused,
         isPending,
+        isPlaceholderData,
         total,
     } = controllerProps;
 
-    const showLoading =
+    const shouldRenderLoading =
         isPending && !isPaused && loading !== false && loading !== undefined;
-    const showOffline = isPaused && offline !== false && offline !== undefined;
-    const showError = controllerError && error !== false && error !== undefined;
-    const showEmpty =
+    const shouldRenderOffline =
+        isPaused &&
+        (isPending || isPlaceholderData) &&
+        offline !== false &&
+        offline !== undefined;
+    const shouldRenderError =
+        controllerError && error !== false && error !== undefined;
+    const shouldRenderEmpty =
         empty !== false &&
         empty !== undefined &&
         // there is no error
@@ -142,13 +148,13 @@ export const ReferenceManyFieldBase = <
     return (
         <ResourceContextProvider value={reference}>
             <ListContextProvider value={controllerProps}>
-                {showLoading
+                {shouldRenderLoading
                     ? loading
-                    : showOffline
+                    : shouldRenderOffline
                       ? offline
-                      : showError
+                      : shouldRenderError
                         ? error
-                        : showEmpty
+                        : shouldRenderEmpty
                           ? empty
                           : render
                             ? render(controllerProps)

packages/ra-ui-materialui/src/field/ReferenceManyField.spec.tsx

@@ -12,10 +12,12 @@ import { Pagination } from '../list/pagination/Pagination';
 import {
     Basic,
     Empty,
+    Offline,
     WithPagination,
     WithPaginationAndSelectAllLimit,
     WithRenderProp,
 } from './ReferenceManyField.stories';
+import { Alert } from '@mui/material';
 
 const theme = createTheme();
 
@@ -207,7 +209,7 @@ describe('<ReferenceManyField />', () => {
         });
     });
 
-    it('should use render prop when provides', async () => {
+    it('should use render prop when provided', async () => {
         render(<WithRenderProp />);
         await waitFor(() => {
             expect(screen.queryAllByRole('progressbar')).toHaveLength(0);
@@ -437,4 +439,41 @@ describe('<ReferenceManyField />', () => {
             );
         });
     });
+    it('should render the default offline component node when offline', async () => {
+        render(<Offline />);
+        fireEvent.click(await screen.findByText('Simulate offline'));
+        fireEvent.click(await screen.findByText('Toggle Child'));
+        await screen.findByText('No connectivity. Could not fetch data.');
+        fireEvent.click(await screen.findByText('Simulate online'));
+        await screen.findByText("Harry Potter and the Philosopher's Stone");
+        expect(
+            screen.queryByText('No connectivity. Could not fetch data.')
+        ).toBeNull();
+        fireEvent.click(await screen.findByText('Simulate offline'));
+        await screen.findByText('You are offline, the data may be outdated');
+        fireEvent.click(screen.getByLabelText('Go to page 2'));
+        await screen.findByText('No connectivity. Could not fetch data.');
+        fireEvent.click(screen.getByLabelText('Go to page 1'));
+        await screen.findByText("Harry Potter and the Philosopher's Stone");
+        fireEvent.click(await screen.findByText('Simulate online'));
+    });
+    it('should render the custom offline component node when offline', async () => {
+        const CustomOffline = () => {
+            return <Alert severity="warning">You are offline!</Alert>;
+        };
+        render(<Offline offline={<CustomOffline />} />);
+        fireEvent.click(await screen.findByText('Simulate offline'));
+        fireEvent.click(await screen.findByText('Toggle Child'));
+        await screen.findByText('You are offline!');
+        fireEvent.click(await screen.findByText('Simulate online'));
+        await screen.findByText("Harry Potter and the Philosopher's Stone");
+        expect(screen.queryByText('You are offline!')).toBeNull();
+        fireEvent.click(await screen.findByText('Simulate offline'));
+        await screen.findByText('You are offline, the data may be outdated');
+        fireEvent.click(screen.getByLabelText('Go to page 2'));
+        await screen.findByText('You are offline!');
+        fireEvent.click(screen.getByLabelText('Go to page 1'));
+        await screen.findByText("Harry Potter and the Philosopher's Stone");
+        fireEvent.click(await screen.findByText('Simulate online'));
+    });
 });

packages/ra-ui-materialui/src/field/ReferenceManyField.stories.tsx

@@ -5,10 +5,12 @@ import {
     RecordContextProvider,
     ResourceContextProvider,
     TestMemoryRouter,
+    useIsOffline,
+    IsOffline,
 } from 'ra-core';
 import { Admin, ListGuesser, Resource } from 'react-admin';
 import type { AdminProps } from 'react-admin';
-import { ThemeProvider, Box, Stack } from '@mui/material';
+import { Alert, ThemeProvider, Box, Stack } from '@mui/material';
 import { createTheme } from '@mui/material/styles';
 import fakeDataProvider from 'ra-data-fakerest';
 import polyglotI18nProvider from 'ra-i18n-polyglot';
@@ -29,6 +31,7 @@ import { TextInput } from '../input';
 import { Edit } from '../detail';
 import { SimpleForm } from '../form';
 import { SelectAllButton, BulkDeleteButton } from '../button';
+import { onlineManager } from '@tanstack/react-query';
 
 export default { title: 'ra-ui-materialui/fields/ReferenceManyField' };
 
@@ -313,3 +316,75 @@ export const WithRenderProp = () => (
         />
     </Wrapper>
 );
+
+export const Offline = ({ offline }: { offline?: React.ReactNode }) => (
+    <Wrapper
+        i18nProvider={polyglotI18nProvider(() => englishMessages)}
+        dataProvider={defaultDataProvider}
+        record={authors[3]}
+    >
+        <RenderChildOnDemand>
+            <ReferenceManyField
+                reference="books"
+                target="author_id"
+                pagination={<Pagination />}
+                perPage={5}
+                offline={offline}
+            >
+                <IsOffline>
+                    <Alert severity="warning">
+                        You are offline, the data may be outdated
+                    </Alert>
+                </IsOffline>
+                <DataTable>
+                    <DataTable.Col source="title" />
+                </DataTable>
+            </ReferenceManyField>
+        </RenderChildOnDemand>
+        <SimulateOfflineButton />
+    </Wrapper>
+);
+
+const CustomOffline = () => {
+    return <Alert severity="warning">You are offline!</Alert>;
+};
+
+Offline.args = {
+    offline: 'default',
+};
+
+Offline.argTypes = {
+    offline: {
+        name: 'Offline component',
+        control: { type: 'radio' },
+        options: ['default', 'custom'],
+        mapping: {
+            default: undefined,
+            custom: <CustomOffline />,
+        },
+    },
+};
+
+const SimulateOfflineButton = () => {
+    const isOffline = useIsOffline();
+    return (
+        <button
+            type="button"
+            onClick={() => onlineManager.setOnline(isOffline)}
+        >
+            {isOffline ? 'Simulate online' : 'Simulate offline'}
+        </button>
+    );
+};
+
+const RenderChildOnDemand = ({ children }) => {
+    const [showChild, setShowChild] = React.useState(false);
+    return (
+        <>
+            <button onClick={() => setShowChild(!showChild)}>
+                Toggle Child
+            </button>
+            {showChild && <div>{children}</div>}
+        </>
+    );
+};

packages/ra-ui-materialui/src/field/ReferenceManyField.tsx

@@ -8,6 +8,7 @@ import {
 
 import { Typography } from '@mui/material';
 import type { FieldProps } from './types';
+import { Offline } from '../Offline';
 
 /**
  * Render related records to the current one.
@@ -62,7 +63,15 @@ export const ReferenceManyField = <
     props: ReferenceManyFieldProps<RecordType, ReferenceRecordType>
 ) => {
     const translate = useTranslate();
-    const { children, pagination, empty, ...controllerProps } = props;
+    const {
+        children,
+        pagination,
+        empty,
+        offline = defaultOffline,
+        render,
+        ...controllerProps
+    } = props;
+
     return (
         <ReferenceManyFieldBase<RecordType, ReferenceRecordType>
             {...controllerProps}
@@ -75,17 +84,35 @@ export const ReferenceManyField = <
                     empty
                 )
             }
-        >
-            {children}
-            {pagination}
-        </ReferenceManyFieldBase>
+            render={props => {
+                const { isPaused, isPending, isPlaceholderData } = props;
+                const shouldRenderOffline =
+                    isPaused &&
+                    (isPending || isPlaceholderData) &&
+                    offline !== undefined &&
+                    offline !== false;
+
+                return (
+                    <>
+                        {shouldRenderOffline
+                            ? offline
+                            : render
+                              ? render(props)
+                              : children}
+                        {pagination}
+                    </>
+                );
+            }}
+        />
     );
 };
 
+const defaultOffline = <Offline variant="inline" />;
+
 export interface ReferenceManyFieldProps<
     RecordType extends Record<string, any> = Record<string, any>,
     ReferenceRecordType extends RaRecord = RaRecord,
 > extends Omit<FieldProps<RecordType>, 'source'>,
         ReferenceManyFieldBaseProps<RecordType, ReferenceRecordType> {
-    pagination?: React.ReactElement;
+    pagination?: React.ReactNode;
 }