fix: deduplicate item ids on add favorites (#256)

Author: spaenleh

src/mutations/member.test.ts

@@ -357,6 +357,49 @@ describe('Member Mutations', () => {
       expect(newData).toEqualImmutable(response);
     });
 
+    it(`Adding duplicated favorite item should dedupe`, async () => {
+      const response = MEMBER_RESPONSE.set(
+        'extra',
+        convertJs({ favoriteItems: ['item-id'] }),
+      );
+      // set random data in cache
+      queryClient.setQueryData(CURRENT_MEMBER_KEY, response);
+      const endpoints = [
+        {
+          response,
+          method: HttpMethod.PATCH,
+          route,
+        },
+      ];
+      const mockedMutation = await mockMutation({
+        mutation,
+        wrapper,
+        endpoints,
+      });
+
+      await act(async () => {
+        await mockedMutation.mutate({
+          memberId: id,
+          itemId,
+          extra: { favoriteItems: ['item-id'] },
+        });
+        await waitForMutation();
+      });
+
+      expect(
+        queryClient.getQueryState(CURRENT_MEMBER_KEY)?.isInvalidated,
+      ).toBeTruthy();
+      expect(mockedNotifier).toHaveBeenCalledWith({
+        type: addFavoriteItemRoutine.SUCCESS,
+      });
+
+      // verify cache keys
+      const newData = queryClient.getQueryData(
+        CURRENT_MEMBER_KEY,
+      ) as MemberRecord;
+      expect(newData).toEqualImmutable(response);
+    });
+
     it(`Unauthorized`, async () => {
       // set random data in cache
       queryClient.setQueryData(CURRENT_MEMBER_KEY, MEMBER_RESPONSE);

src/mutations/member.ts

@@ -143,13 +143,18 @@ export default (queryClient: QueryClient, queryConfig: QueryClientConfig) => {
   // mutation to update favorite items of given member
   queryClient.setMutationDefaults(ADD_FAVORITE_ITEM, {
     mutationFn: ({ memberId, itemId, extra: prevExtra }) => {
-      const newFavoriteItems = prevExtra.favoriteItems
-        ? prevExtra.favoriteItems.concat([itemId])
+      const favoriteItems = prevExtra.favoriteItems
+        ? prevExtra.favoriteItems.concat(
+            prevExtra.favoriteItems.includes(itemId) ? [] : [itemId],
+          )
         : [itemId];
       return Api.editMember(
         {
           id: memberId,
-          extra: { ...prevExtra, favoriteItems: newFavoriteItems },
+          extra: {
+            ...prevExtra,
+            favoriteItems,
+          },
         },
         queryConfig,
       ).then((member) => convertJs(member));
@@ -164,12 +169,14 @@ export default (queryClient: QueryClient, queryConfig: QueryClientConfig) => {
 
       // Optimistically update to the new value
       const { itemId, extra } = payload;
-      const newFavoriteItems = extra.favoriteItems
-        ? extra.favoriteItems.concat([itemId])
+      const favoriteItems = extra.favoriteItems
+        ? extra.favoriteItems.concat(
+            extra.favoriteItems.includes(itemId) ? [] : [itemId],
+          )
         : [itemId];
 
       const member = convertJs({
-        extra: { ...extra, favoriteItems: newFavoriteItems },
+        extra: { ...extra, favoriteItems },
       });
 
       queryClient.setQueryData(