feat(graphiql-fetcher): better detection for subscription and unit tests

src/graphiql-fetcher.ts

@@ -1,5 +1,17 @@
 import { SubscriptionClient } from './client';
 
+const hasSubscriptionOperation = (graphQlParams: any) => {
+  const query = graphQlParams.query;
+  const operationName = graphQlParams.operationName;
+
+  if (operationName && operationName !== '') {
+    return query.includes(`subscription ${operationName}`);
+  }
+
+  return query.includes('subscription {') ||
+    query.includes('subscription{');
+};
+
 export const graphQLFetcher = (subscriptionsClient: SubscriptionClient, fallbackFetcher: Function) => {
   let activeSubscriptionId: number | null = null;
 
@@ -8,7 +20,7 @@ export const graphQLFetcher = (subscriptionsClient: SubscriptionClient, fallback
       subscriptionsClient.unsubscribe(activeSubscriptionId);
     }
 
-    if (subscriptionsClient && graphQLParams.query.startsWith('subscription')) {
+    if (subscriptionsClient && hasSubscriptionOperation(graphQLParams)) {
       return {
         subscribe: (observer: { error: Function, next: Function }) => {
           observer.next('Your subscription data will appear here after server publication!');

src/test/tests.ts

@@ -33,6 +33,8 @@ import {
   GRAPHQL_SUBSCRIPTIONS,
 } from '../protocols';
 
+import { graphQLFetcher } from '../graphiql-fetcher';
+
 import {createServer, IncomingMessage, ServerResponse} from 'http';
 import {SubscriptionServer} from '../server';
 import {SubscriptionClient} from '../client';
@@ -1268,3 +1270,71 @@ describe('Server', function () {
     };
   });
 });
+
+describe('GraphiQL Fetcher', () => {
+  let subscriptionsClient = {
+    subscribe: sinon.spy(),
+    unsubscribe: sinon.spy(),
+  };
+
+  let fallbackFetcher = sinon.spy();
+
+  let fetcher: Function;
+
+  beforeEach(() => {
+    subscriptionsClient.subscribe.reset();
+    subscriptionsClient.unsubscribe.reset();
+    fallbackFetcher.reset();
+    fetcher = graphQLFetcher(<any>subscriptionsClient, fallbackFetcher);
+  });
+
+  it('should use subscriptions fetcher when using with named operation', () => {
+    const ret = fetcher({
+      query: 'subscription commentAdded { field }',
+      operationName: 'commentAdded',
+    });
+
+    expect(ret.subscribe).not.to.equals(undefined);
+  });
+
+  it('should use subscriptions fetcher when using with named operation with fragments', () => {
+    const ret = fetcher({
+      query: 'fragment f { field } subscription commentAdded { ...f }',
+      operationName: 'commentAdded',
+    });
+
+    expect(ret.subscribe).not.to.equals(undefined);
+  });
+
+  it('should use subscriptions fetcher when using with operation with fragments', () => {
+    const ret = fetcher({
+      query: 'fragment f { field } subscription { ...f }',
+    });
+
+    expect(ret.subscribe).not.to.equals(undefined);
+  });
+
+  it('should use subscriptions fetcher when using with operation', () => {
+    const ret = fetcher({
+      query: 'subscription { ...f }',
+    });
+
+    expect(ret.subscribe).not.to.equals(undefined);
+  });
+
+  it('should use fallback fetcher when using query', () => {
+    fetcher({
+      query: 'query { field }',
+    });
+
+    assert(fallbackFetcher.calledOnce);
+  });
+
+  it('should use fallback fetcher when using mutations', () => {
+    fetcher({
+      query: 'mutation { field }',
+    });
+
+    assert(fallbackFetcher.calledOnce);
+  });
+});