From 254eb40f515f608a549f77c50fd47d207ec74190 Mon Sep 17 00:00:00 2001
From: klarstrup <jonas@klarstrup.dk>
Date: Fri, 24 Apr 2020 05:06:30 +0200
Subject: [PATCH 1/4] Handle empty empty response object in typePatchers

---
 src/restLink.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/restLink.ts b/src/restLink.ts
index e642b47..e4dc4de 100755
--- a/src/restLink.ts
+++ b/src/restLink.ts
@@ -1183,6 +1183,8 @@ export class RestLink extends ApolloLink {
 
     if (typePatcher == null) {
       this.typePatcher = (result, __typename, _2) => {
+        if (!Object.keys(result).length) return null;
+
         return { __typename, ...result };
       };
     } else if (
@@ -1202,6 +1204,8 @@ export class RestLink extends ApolloLink {
         outerType: string,
         patchDeeper: RestLink.FunctionalTypePatcher,
       ) => {
+        if (!Object.keys(data).length) return null;
+
         const __typename = data.__typename || outerType;
         if (Array.isArray(data)) {
           return data.map(d => patchDeeper(d, __typename, patchDeeper));

From c106c637420b361e29f092adf5bc3846c9013622 Mon Sep 17 00:00:00 2001
From: klarstrup <jonas@klarstrup.dk>
Date: Fri, 24 Apr 2020 05:06:51 +0200
Subject: [PATCH 2/4] handle empty selectionSet under @rest

---
 src/restLink.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/restLink.ts b/src/restLink.ts
index e4dc4de..de60fd0 100755
--- a/src/restLink.ts
+++ b/src/restLink.ts
@@ -392,6 +392,7 @@ function insertNullsForAnyOmittedFields(
   currentSelectionSet: SelectionSetNode,
 ): void {
   if (
+    currentSelectionSet == null ||
     null == current ||
     typeof current === 'number' ||
     typeof current === 'boolean' ||

From ef16a62a864812873525135645cb44249fc7f23f Mon Sep 17 00:00:00 2001
From: klarstrup <jonas@klarstrup.dk>
Date: Fri, 24 Apr 2020 05:07:21 +0200
Subject: [PATCH 3/4] Test handling of empty object responses with and without
 a typePatcher

---
 src/__tests__/restLink.ts | 59 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/src/__tests__/restLink.ts b/src/__tests__/restLink.ts
index 9eb44bf..9a5c2b5 100755
--- a/src/__tests__/restLink.ts
+++ b/src/__tests__/restLink.ts
@@ -2578,6 +2578,65 @@ describe('Mutation', () => {
       });
     });
 
+    it.only('returns null on empty object response without typePatcher', async () => {
+      // In truth this test is just for show, because the fetch implementation
+      // used in the tests already returns {} from res.json() for 204 responses
+      expect.assertions(1);
+
+      const link = new RestLink({ uri: '/api' });
+
+      const post = { id: '1', title: 'Love apollo' };
+      fetchMock.post('/api/posts', {
+        status: 204,
+        body: {},
+      });
+
+      const createPostMutation = gql`
+        mutation publishPost($input: PublishablePostInput!) {
+          publishedPost(input: $input) @rest(path: "/posts", method: "POST")
+        }
+      `;
+      const response = await toPromise<Result>(
+        execute(link, {
+          operationName: 'publishPost',
+          query: createPostMutation,
+          variables: { input: { title: post.title } },
+        }),
+      );
+
+      expect(response.data.publishedPost).toEqual(null);
+    });
+
+    it.only('returns null on empty object response with typePatcher', async () => {
+      // In truth this test is just for show, because the fetch implementation
+      // used in the tests already returns {} from res.json() for 204 responses
+      expect.assertions(1);
+
+      const link = new RestLink({
+        uri: '/api',
+        typePatcher: { Post: data => data },
+      });
+
+      const post = { id: '1', title: 'Love apollo' };
+
+      fetchMock.post('/api/posts', { status: 204, body: {} });
+
+      const createPostMutation = gql`
+        mutation publishPost($input: PublishablePostInput!) {
+          publishedPost(input: $input) @rest(path: "/posts", method: "POST")
+        }
+      `;
+      const response = await toPromise<Result>(
+        execute(link, {
+          operationName: 'publishPost',
+          query: createPostMutation,
+          variables: { input: { title: post.title } },
+        }),
+      );
+
+      expect(response.data.publishedPost).toEqual(null);
+    });
+
     it('returns an empty object on successful posts with zero Content-Length', async () => {
       // In Node.js parsing an empty body doesn't throw an error, so the best test is
       // to provide body data and ensure the zero length still triggers the empty response

From a6623bc2690eebab3639cf1bbbb2a249ef63d8f9 Mon Sep 17 00:00:00 2001
From: klarstrup <jonas@klarstrup.dk>
Date: Fri, 24 Apr 2020 05:17:12 +0200
Subject: [PATCH 4/4] remove irrelevant comments in tests

---
 src/__tests__/restLink.ts | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/src/__tests__/restLink.ts b/src/__tests__/restLink.ts
index 9a5c2b5..e3356e8 100755
--- a/src/__tests__/restLink.ts
+++ b/src/__tests__/restLink.ts
@@ -2579,8 +2579,6 @@ describe('Mutation', () => {
     });
 
     it.only('returns null on empty object response without typePatcher', async () => {
-      // In truth this test is just for show, because the fetch implementation
-      // used in the tests already returns {} from res.json() for 204 responses
       expect.assertions(1);
 
       const link = new RestLink({ uri: '/api' });
@@ -2608,8 +2606,6 @@ describe('Mutation', () => {
     });
 
     it.only('returns null on empty object response with typePatcher', async () => {
-      // In truth this test is just for show, because the fetch implementation
-      // used in the tests already returns {} from res.json() for 204 responses
       expect.assertions(1);
 
       const link = new RestLink({