Convert trends to React Query

app/soapbox/features/ui/components/trends-panel.tsx

@@ -1,40 +1,32 @@
 import * as React from 'react';
 import { FormattedMessage } from 'react-intl';
-import { useDispatch } from 'react-redux';
 
-import { fetchTrends } from 'soapbox/actions/trends';
 import Hashtag from 'soapbox/components/hashtag';
 import { Widget } from 'soapbox/components/ui';
-import { useAppSelector } from 'soapbox/hooks';
+import useTrends from 'soapbox/queries/trends';
 
 interface ITrendsPanel {
   limit: number
 }
 
 const TrendsPanel = ({ limit }: ITrendsPanel) => {
-  const dispatch = useDispatch();
-
-  const trends = useAppSelector((state) => state.trends.items);
+  const { data: trends, isFetching } = useTrends();
 
   const sortedTrends = React.useMemo(() => {
-    return trends.sort((a, b) => {
+    return trends?.sort((a, b) => {
       const num_a = Number(a.getIn(['history', 0, 'accounts']));
       const num_b = Number(b.getIn(['history', 0, 'accounts']));
       return num_b - num_a;
     }).slice(0, limit);
   }, [trends, limit]);
 
-  React.useEffect(() => {
-    dispatch(fetchTrends());
-  }, []);
-
-  if (sortedTrends.isEmpty()) {
+  if (trends?.length === 0 || isFetching) {
     return null;
   }
 
   return (
     <Widget title={<FormattedMessage id='trends.title' defaultMessage='Trends' />}>
-      {sortedTrends.map((hashtag) => (
+      {sortedTrends?.slice(0, limit).map((hashtag) => (
         <Hashtag key={hashtag.name} hashtag={hashtag} />
       ))}
     </Widget>

app/soapbox/queries/__tests__/trends.test.ts

@@ -0,0 +1,42 @@
+import { __stub } from 'soapbox/api';
+import { renderHook, waitFor } from 'soapbox/jest/test-helpers';
+
+import useTrends from '../trends';
+
+describe('useTrends', () => {
+  describe('with a successul query', () => {
+    beforeEach(() => {
+      __stub((mock) => {
+        mock.onGet('/api/v1/trends')
+          .reply(200, [
+            { name: '#golf', url: 'https://example.com' },
+            { name: '#tennis', url: 'https://example.com' },
+          ]);
+      });
+    });
+
+    it('is successful', async() => {
+      const { result } = renderHook(() => useTrends());
+
+      await waitFor(() => expect(result.current.isFetching).toBe(false));
+
+      expect(result.current.data?.length).toBe(2);
+    });
+  });
+
+  describe('with an unsuccessul query', () => {
+    beforeEach(() => {
+      __stub((mock) => {
+        mock.onGet('/api/v1/trends').networkError();
+      });
+    });
+
+    it('is successful', async() => {
+      const { result } = renderHook(() => useTrends());
+
+      await waitFor(() => expect(result.current.isFetching).toBe(false));
+
+      expect(result.current.error).toBeDefined();
+    });
+  });
+});

app/soapbox/queries/trends.ts

@@ -0,0 +1,28 @@
+import { useQuery } from '@tanstack/react-query';
+
+import { fetchTrendsSuccess } from 'soapbox/actions/trends';
+import { useApi, useAppDispatch } from 'soapbox/hooks';
+import { normalizeTag } from 'soapbox/normalizers';
+
+import type { Tag } from 'soapbox/types/entities';
+
+export default function useTrends() {
+  const api = useApi();
+  const dispatch = useAppDispatch();
+
+  const getTrends = async() => {
+    const { data } = await api.get<Tag[]>('/api/v1/trends');
+
+    dispatch(fetchTrendsSuccess(data));
+
+    const normalizedData = data.map((tag) => normalizeTag(tag));
+    return normalizedData;
+  };
+
+  const result = useQuery<Tag[]>(['trends'], getTrends, {
+    placeholderData: [],
+    staleTime: 600000, // 10 minutes
+  });
+
+  return result;
+}