From ef63a2f41d341d8d5cc726ef9837fceb660b1d34 Mon Sep 17 00:00:00 2001
From: Jonas Helfer <jonas@helfer.email>
Date: Thu, 10 Nov 2016 19:33:48 -0800
Subject: [PATCH 1/2] sanity-check server response in batching NI

---
 src/transport/batchedNetworkInterface.ts |  5 ++
 test/client.ts                           | 61 ++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/src/transport/batchedNetworkInterface.ts b/src/transport/batchedNetworkInterface.ts
index 0fd776b74f1..56a28c373ec 100644
--- a/src/transport/batchedNetworkInterface.ts
+++ b/src/transport/batchedNetworkInterface.ts
@@ -69,6 +69,11 @@ export class HTTPBatchedNetworkInterface extends HTTPFetchNetworkInterface {
           })
           .then(responses => {
 
+
+            if (typeof responses.map !== 'function') {
+              throw new Error('BatchingNetworkInterface: server response is not an array');
+            }
+
             type ResponseAndOptions = {
               response: IResponse;
               options: RequestInit;
diff --git a/test/client.ts b/test/client.ts
index 279a404f85c..fe378532693 100644
--- a/test/client.ts
+++ b/test/client.ts
@@ -1718,6 +1718,67 @@ describe('client', () => {
     });
   });
 
+  it('should throw an error if response to batch request is not an array', (done) => {
+    const firstQuery = gql`
+      query {
+        author {
+          firstName
+          lastName
+        }
+      }`;
+    const firstResult = {
+      data: {
+        author: {
+          firstName: 'John',
+          lastName: 'Smith',
+        },
+      },
+      loading: false,
+    };
+    const secondQuery = gql`
+      query {
+        person {
+          name
+        }
+      }`;
+    const url = 'http://not-a-real-url.com';
+    const oldFetch = fetch;
+    fetch = createMockFetch({
+      url,
+      opts: {
+        body: JSON.stringify([
+          {
+            query: print(firstQuery),
+          },
+          {
+            query: print(secondQuery),
+          },
+        ]),
+        headers: {
+          Accept: '*/*',
+          'Content-Type': 'application/json',
+        },
+        method: 'POST',
+      },
+      result: createMockedIResponse(firstResult),
+    });
+    const networkInterface = createBatchingNetworkInterface({
+      uri: 'http://not-a-real-url.com',
+      batchInterval: 5,
+      opts: {},
+    });
+    Promise.all([
+      networkInterface.query({ query: firstQuery }),
+      networkInterface.query({ query: secondQuery }),
+    ]).then((results) => {
+      assert.equal(true, false, 'expected response to throw an error');
+    }).catch( e => {
+      assert.equal(e.message, 'BatchingNetworkInterface: server response is not an array');
+      fetch = oldFetch;
+      done();
+    });
+  });
+
   it('should not do transport-level batching when the interval is exceeded', (done) => {
     const firstQuery = gql`
       query {

From cfca01f8d4a9ebdd5a790e2eb678465889c76598 Mon Sep 17 00:00:00 2001
From: Jonas Helfer <jonas@helfer.email>
Date: Thu, 10 Nov 2016 19:40:32 -0800
Subject: [PATCH 2/2] update CHANGELOG.md

---
 CHANGELOG.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 924690aa5ca..46679abd58a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,11 +3,11 @@
 Expect active development and potentially significant breaking changes in the `0.x` track. We'll try to be diligent about releasing a `1.0` version in a timely fashion (ideally within 3 to 6 months), to signal the start of a more stable API.
 
 ### vNEXT
+- Print a warning if server response is not an array when using transport batching [PR #893](https://github.com/apollostack/apollo-client/pull/893)
 
 ### 0.5.1
 - **new Feature**: Enable chaining of `use` and `useAfter` function calls in network interface. [PR #860](https://github.com/apollostack/apollo-client/pull/860) [Issue #564](https://github.com/apollostack/apollo-client/issues/564)
-- Create and expose the `MutationOptions` [PR #866]
-(https://github.com/apollostack/apollo-client/pull/866)
+- Create and expose the `MutationOptions` [PR #866](https://github.com/apollostack/apollo-client/pull/866)
 - Expose `SubscriptionOptions` [PR #868](https://github.com/apollostack/apollo-client/pull/868)
 - Fix issue with `currentResult` and optimistic responses [Issue #877](https://github.com/apollostack/apollo-client/issues/877)
 - Provide an onError callback for subscribeToMore [PR #886](https://github.com/apollostack/apollo-client/issues/886)