From e8e49026dd0529c010e6134ce4403677240d1649 Mon Sep 17 00:00:00 2001
From: Chris Airey <cairey@mindgrub.com>
Date: Wed, 23 Jan 2019 16:20:35 -0500
Subject: [PATCH 1/2] Serialize arrays as JSON on fetch in RESTDataSource

---
 CHANGELOG.md                                  |  2 ++
 packages/apollo-datasource-rest/package.json  |  2 +-
 .../src/RESTDataSource.ts                     |  3 ++-
 .../src/__tests__/RESTDataSource.test.ts      | 25 +++++++++++++++++++
 4 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fef4226084c..47f965fbac0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ### vNEXT
 
+- Fix: Serialize arrays as JSON on fetch in `RESTDataSource`. [PR #2219](https://github.com/apollographql/apollo-server/pull/2219)
+
 ### v2.3.3
 
 - `apollo-server` (only): Stop double-invocation of `serverWillStart` life-cycle event.  (More specific integrations - e.g. Express, Koa, Hapi, etc. - were unaffected.) [PR #2239](https://github.com/apollographql/apollo-server/pull/2239)
diff --git a/packages/apollo-datasource-rest/package.json b/packages/apollo-datasource-rest/package.json
index d5b08204802..765adbe5b3d 100644
--- a/packages/apollo-datasource-rest/package.json
+++ b/packages/apollo-datasource-rest/package.json
@@ -1,6 +1,6 @@
 {
   "name": "apollo-datasource-rest",
-  "version": "0.2.2",
+  "version": "0.2.3",
   "author": "opensource@apollographql.com",
   "license": "MIT",
   "repository": {
diff --git a/packages/apollo-datasource-rest/src/RESTDataSource.ts b/packages/apollo-datasource-rest/src/RESTDataSource.ts
index 0c8f9bf1d2c..26d7a492a3c 100644
--- a/packages/apollo-datasource-rest/src/RESTDataSource.ts
+++ b/packages/apollo-datasource-rest/src/RESTDataSource.ts
@@ -218,11 +218,12 @@ export abstract class RESTDataSource<TContext = any> extends DataSource {
       url.searchParams.append(name, value);
     }
 
-    // We accept arbitrary objects as body and serialize them as JSON
+    // We accept arbitrary objects and arrays as body and serialize them as JSON
     if (
       options.body !== undefined &&
       options.body !== null &&
       (options.body.constructor === Object ||
+        Array.isArray(options.body) ||
         ((options.body as any).toJSON &&
           typeof (options.body as any).toJSON === 'function'))
     ) {
diff --git a/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts b/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts
index 48868de308f..477ad4cc384 100644
--- a/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts
+++ b/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts
@@ -268,6 +268,31 @@ describe('RESTDataSource', () => {
       );
     });
 
+    it('serializes a request body that is an array as JSON', async () => {
+      const dataSource = new class extends RESTDataSource {
+        baseURL = 'https://api.example.com';
+
+        postFoo(foo) {
+          return this.post('foo', foo);
+        }
+      }();
+
+      dataSource.httpCache = httpCache;
+
+      fetch.mockJSONResponseOnce();
+
+      await dataSource.postFoo(['foo', 'bar']);
+
+      expect(fetch.mock.calls.length).toEqual(1);
+      expect(fetch.mock.calls[0][0].url).toEqual('https://api.example.com/foo');
+      expect(fetch.mock.calls[0][0].body).toEqual(
+        JSON.stringify(['foo', 'bar']),
+      );
+      expect(fetch.mock.calls[0][0].headers.get('Content-Type')).toEqual(
+        'application/json',
+      );
+    });
+
     it('serializes a request body that has a toJSON method as JSON', async () => {
       const dataSource = new class extends RESTDataSource {
         baseURL = 'https://api.example.com';

From f99ebd373b682b81fd1e3fcc6fe6e409074ddbc4 Mon Sep 17 00:00:00 2001
From: Jesse Rosenberger <git@jro.cc>
Date: Tue, 5 Feb 2019 13:11:43 +0200
Subject: [PATCH 2/2] Set `apollo-datasource-rest` version back to v0.2.2.

Lerna will take care of this on publishing.
---
 packages/apollo-datasource-rest/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/apollo-datasource-rest/package.json b/packages/apollo-datasource-rest/package.json
index 765adbe5b3d..d5b08204802 100644
--- a/packages/apollo-datasource-rest/package.json
+++ b/packages/apollo-datasource-rest/package.json
@@ -1,6 +1,6 @@
 {
   "name": "apollo-datasource-rest",
-  "version": "0.2.3",
+  "version": "0.2.2",
   "author": "opensource@apollographql.com",
   "license": "MIT",
   "repository": {