✨ Follow 기능 구현

src/app/layout/RootLayout.tsx

@@ -11,7 +11,7 @@ import './RootLayout.scss';
  */
 export const RootLayout = () => {
   return (
-    <IPhoneLayout>
+    <IPhoneLayout defaultSize={85}>
       <div className='wrap'>
         <Outlet />
       </div>

src/app/mocks/consts/relationshipStatus.ts

@@ -11,7 +11,7 @@ export const relationshipStatus: Relationship = {
   3: 'pending',
   4: 'none',
   5: 'following',
-  6: 'pending',
+  6: 'none',
   7: 'following',
   8: 'none',
   9: 'none',

src/app/mocks/handler/follow.ts

@@ -26,17 +26,20 @@ export const followHandler = [
       case 'none':
         if (users[formattedUserId].locked) {
           relationshipStatus[formattedUserId] = 'pending';
-        } else relationshipStatus[formattedUserId] = 'following';
-        break;
+          return createHttpSuccessResponse({ relationshipStatus: 'pending' });
+        } else {
+          users[formattedUserId].followerCount += 1;
+          users[1].followingCount += 1;
+          relationshipStatus[formattedUserId] = 'following';
+          return createHttpSuccessResponse({ relationshipStatus: 'following' });
+        }
       case 'following':
         return createHttpErrorResponse('4220');
       case 'pending':
         return createHttpErrorResponse('4220');
       default:
         return createHttpErrorResponse('4040');
     }
-
-    return createHttpSuccessResponse({});
   }),
   // 2️⃣ 언팔로우 & 팔로우 요청 취소
   http.delete('/users/:user_id/follow', ({ params }) => {
@@ -56,16 +59,15 @@ export const followHandler = [
         return createHttpErrorResponse('4220');
       case 'following':
         relationshipStatus[formattedUserId] = 'none';
-        break;
+        users[formattedUserId].followerCount -= 1;
+        users[1].followingCount -= 1;
+        return createHttpSuccessResponse({ relationshipStatus: 'none' });
       case 'pending':
         relationshipStatus[formattedUserId] = 'none';
-        break;
-
+        return createHttpSuccessResponse({ relationshipStatus: 'none' });
       default:
         return createHttpErrorResponse('4040');
     }
-
-    return createHttpSuccessResponse({});
   }),
   // 3️⃣ 팔로우 확인
   http.get('/users/:user_id/follow', ({ params }) => {

src/features/follow/api/index.ts

@@ -0,0 +1 @@
+export { useFollow } from './useFollow';

src/features/follow/api/useFollow.tsx

@@ -0,0 +1,74 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { requestFollow, requestUnfollow } from '@/shared/axios';
+import { FetchRelationshipStatus } from '@/shared/consts';
+import { QUERY_KEYS } from '@/shared/react-query';
+import { isErrorResponse } from '@/shared/utils';
+
+import { updateRelationshipStatus } from '../lib';
+
+export const useFollow = (
+  userId: number,
+  locked: boolean,
+  isFollow: boolean,
+) => {
+  const queryClient = useQueryClient();
+
+  const {
+    data,
+    mutate: handleFollow,
+    isPending: isPendingFollow,
+  } = useMutation({
+    mutationKey: [QUERY_KEYS.follow],
+    mutationFn: () =>
+      isFollow ? requestFollow(userId) : requestUnfollow(userId),
+    onMutate: async () => {
+      await queryClient.cancelQueries({
+        queryKey: [QUERY_KEYS.follow, userId],
+      });
+
+      const previousQueryData =
+        queryClient.getQueryData<FetchRelationshipStatus>([
+          QUERY_KEYS.follow,
+          userId,
+        ]);
+
+      if (!previousQueryData) return;
+
+      const updatedQueryData = updateRelationshipStatus(
+        previousQueryData,
+        locked,
+      );
+
+      await queryClient.setQueryData(
+        [QUERY_KEYS.follow, userId],
+        updatedQueryData,
+      );
+
+      return { previousQueryData };
+    },
+    onError: (_, __, context) => {
+      queryClient.setQueryData(
+        [QUERY_KEYS.follow, userId],
+        context?.previousQueryData,
+      );
+    },
+    onSuccess: (response, _, context) => {
+      if (isErrorResponse(response)) {
+        queryClient.setQueryData(
+          [QUERY_KEYS.follow, userId],
+          context.previousQueryData,
+        );
+      }
+    },
+    onSettled: () => {
+      queryClient.invalidateQueries({ queryKey: [QUERY_KEYS.follow, userId] });
+      queryClient.invalidateQueries({
+        queryKey: [QUERY_KEYS.users, userId],
+      });
+      queryClient.invalidateQueries({ queryKey: [QUERY_KEYS.users, 1] });
+    },
+  });
+
+  return { data, handleFollow, isPendingFollow };
+};

src/features/follow/index.ts

@@ -0,0 +1 @@
+export { useFollow } from './api';

src/features/follow/lib/index.ts

@@ -0,0 +1 @@
+export { updateRelationshipStatus } from './updateRelationshipStatus';

src/features/follow/lib/updateRelationshipStatus.ts

@@ -0,0 +1,40 @@
+import { RelationshipStatus, FetchRelationshipStatus } from '@/shared/consts';
+
+/**
+ * 팔로우, 언팔로우/팔로우 취소에 따라 변경된 관계 상태를 계산하는 함수
+ * @param relationshipStatus 이전 관계 상태
+ * @param locked 비공개 계정 여부
+ */
+
+const RelationshipStatusCalculate = (
+  relationshipStatus: RelationshipStatus,
+  locked: boolean,
+) => {
+  switch (relationshipStatus) {
+    case 'self':
+      return 'self';
+    case 'following':
+      return 'none';
+    case 'none':
+      return locked ? 'pending' : 'following';
+    case 'pending':
+      return 'none';
+    default:
+      return relationshipStatus;
+  }
+};
+
+export function updateRelationshipStatus(
+  previousRelationshipStatusData: FetchRelationshipStatus,
+  locked: boolean,
+) {
+  return {
+    code: previousRelationshipStatusData.code,
+    data: {
+      relationshipStatus: RelationshipStatusCalculate(
+        previousRelationshipStatusData.data.relationshipStatus,
+        locked,
+      ),
+    },
+  };
+}

src/features/follow/test/useFollow.unit.test.tsx

@@ -0,0 +1,85 @@
+import { renderHook, act, waitFor } from '@testing-library/react';
+import { describe, expect, it } from 'vitest';
+
+import { createQueryClientWrapper } from '@/shared/tests';
+
+import { useFollow } from '../api';
+
+describe('Follow 기능 테스트', () => {
+  describe('none 상태일 때', () => {
+    it('공개 계정이라면 following 상태로 변경된다.', async () => {
+      //given
+      const { result } = renderHook(() => useFollow(9, false, true), {
+        wrapper: createQueryClientWrapper(),
+      });
+
+      //when
+      act(() => result.current.handleFollow());
+
+      //then
+      await waitFor(() => {
+        const {
+          data: { relationshipStatus: initialStatus },
+        } = result.current.data;
+
+        expect(initialStatus).toBe('following');
+      });
+    });
+
+    it('비공개 계정이라면 pending 상태로 변경된다.', async () => {
+      const { result } = renderHook(() => useFollow(4, true, true), {
+        wrapper: createQueryClientWrapper(),
+      });
+
+      act(() => result.current.handleFollow());
+
+      await waitFor(() => {
+        const {
+          data: { relationshipStatus: initialStatus },
+        } = result.current.data;
+
+        expect(initialStatus).toBe('pending');
+      });
+    });
+  });
+});
+
+describe('Unfollow 기능 테스트', () => {
+  it('following 상태일 때, none 상태로 변경된다.', async () => {
+    // given
+    const { result } = renderHook(() => useFollow(2, false, false), {
+      wrapper: createQueryClientWrapper(),
+    });
+
+    // when
+    act(() => result.current.handleFollow());
+
+    // then
+    await waitFor(() => {
+      const {
+        data: { relationshipStatus: initialStatus },
+      } = result.current.data;
+
+      expect(initialStatus).toBe('none');
+    });
+  });
+
+  it('pending 상태일 때, none 상태로 변경된다.', async () => {
+    // given
+    const { result } = renderHook(() => useFollow(3, true, false), {
+      wrapper: createQueryClientWrapper(),
+    });
+
+    //when
+    act(() => result.current.handleFollow());
+
+    //then
+    await waitFor(() => {
+      const {
+        data: { relationshipStatus: initialStatus },
+      } = result.current.data;
+
+      expect(initialStatus).toBe('none');
+    });
+  });
+});

src/shared/axios/follow/follow.ts

@@ -0,0 +1,34 @@
+import { axiosInstance } from '../config/instance';
+
+/**
+ * 팔로우 API
+ * @param userId 유저 아이디
+ * @returns 관계 상태
+ */
+export async function requestFollow(userId: number) {
+  const { data } = await axiosInstance.post(`/users/${userId}/follow`);
+
+  return data;
+}
+
+/**
+ * 언팔로우/팔로우 취소 API
+ * @param userId 유저 아이디
+ * @returns 관계 상태
+ */
+export async function requestUnfollow(userId: number) {
+  const { data } = await axiosInstance.delete(`/users/${userId}/follow`);
+
+  return data;
+}
+
+/**
+ * 팔로우 확인 API
+ * @param userId 유저 아이디
+ * @returns 관계 상태
+ */
+export async function fetchRelationshipStatus(userId: number) {
+  const { data } = await axiosInstance.get(`/users/${userId}/follow`);
+
+  return data;
+}

src/shared/axios/follow/index.ts

@@ -0,0 +1 @@
+export * from './follow';

src/shared/axios/index.ts

@@ -1,3 +1,5 @@
 export { axiosInstance } from './config';
 export * from './like';
 export * from './bookmark';
+export * from './follow';
+export * from './user';

src/shared/axios/user/index.ts

@@ -0,0 +1 @@
+export * from './user';

src/shared/axios/user/user.ts

@@ -0,0 +1,14 @@
+import { FetchUser } from '@/shared/consts';
+
+import { axiosInstance } from '../config/instance';
+
+/**
+ * 유저 정보 API
+ * @param userId 유저 아이디
+ * @returns 유저 정보
+ */
+export async function fetchUser(userId: number): Promise<FetchUser> {
+  const { data } = await axiosInstance.get(`/users/${userId}`);
+
+  return data;
+}

src/shared/react-query/consts/keys.ts

@@ -1,4 +1,5 @@
 export const QUERY_KEYS = Object.freeze({
   feeds: 'feeds',
   users: 'users',
+  follow: 'follow',
 });

src/shared/react-query/dir/handleQuery.ts

@@ -40,7 +40,10 @@ export function handleMutationError(
   mutation: Mutation<unknown, unknown, unknown, unknown>,
 ) {
   const { options } = mutation;
+  const mutationCautionToastKeys = ['feed-report', 'follow'];
 
-  if (options.mutationKey?.includes('feed-report'))
+  if (
+    mutationCautionToastKeys.some((key) => options.mutationKey?.includes(key))
+  )
     showToastHandler('caution', '다시 시도해 주세요');
 }

src/widgets/profile-user/api/index.ts

@@ -1 +1,2 @@
 export { useGetUser } from './useGetUser';
+export { useGetRelationshipStatus } from './useGetRelationshipStatus';

src/widgets/profile-user/api/useGetRelationshipStatus.ts

@@ -0,0 +1,23 @@
+import { useQuery } from '@tanstack/react-query';
+
+import { fetchRelationshipStatus } from '@/shared/axios';
+import { QUERY_KEYS } from '@/shared/react-query';
+
+export const useGetRelationshipStatus = (userId: number) => {
+  const {
+    data: relationshipStatusData,
+    isLoading: relationshipLoading,
+    isError: relationshipError,
+    refetch: refetchRelationshipStatus,
+  } = useQuery({
+    queryKey: [QUERY_KEYS.follow, userId],
+    queryFn: () => fetchRelationshipStatus(userId),
+  });
+
+  return {
+    relationshipStatusData,
+    relationshipLoading,
+    relationshipError,
+    refetchRelationshipStatus,
+  };
+};

src/widgets/profile-user/api/useGetUser.ts

@@ -1,14 +1,8 @@
 import { useQuery } from '@tanstack/react-query';
 
-import { axiosInstance } from '@/shared/axios';
-import { FetchUser } from '@/shared/consts';
+import { fetchUser } from '@/shared/axios';
 import { QUERY_KEYS } from '@/shared/react-query';
 
-async function fetchUser(userId: number): Promise<FetchUser> {
-  const { data } = await axiosInstance.get(`/users/${userId}`);
-  return data;
-}
-
 export const useGetUser = (userId: number) => {
   const {
     data,