add try/catch and test for rejected options

src/integrations/expressApollo.test.ts

@@ -67,6 +67,22 @@ describe('expressApollo', () => {
        expect(() => graphqlHTTP(undefined as ExpressApolloOptions)).to.throw('Apollo Server requires options.');
     });
 
+    it('throws an error if options promise is rejected', () => {
+        const app = express();
+        app.use('/graphql', bodyParser.json());
+        app.use('/graphql', graphqlHTTP( (req) => (Promise.reject({})) as any as ExpressApolloOptions));
+        const expected = 'Invalid options';
+        const req = request(app)
+            .post('/graphql')
+            .send({
+                query: 'query test{ testString }',
+            });
+        return req.then((res) => {
+            expect(res.status).to.equal(500);
+            return expect(res.error.text).to.contain(expected);
+        });
+    });
+
     it('can be called with an options function', () => {
         const app = express();
         app.use('/graphql', bodyParser.json());

src/integrations/expressApollo.ts

@@ -55,7 +55,12 @@ export function graphqlHTTP(options: ExpressApolloOptions | ExpressApolloOptions
   return async (req: express.Request, res: express.Response, next) => {
     let optionsObject: ExpressApolloOptions;
     if (isOptionsFunction(options)) {
-      optionsObject = await options(req);
+      try {
+        optionsObject = await options(req);
+      } catch (e) {
+        res.status(500);
+        res.send(`Invalid options provided to ApolloServer: ${e.message}`);
+      }
     } else {
       optionsObject = options;
     }