Resolve linkify error (#454)

src/store/messages/saga.test.ts

@@ -19,6 +19,7 @@ import {
   editMessage,
   uploadFileMessage,
   receiveNewMessage,
+  getPreview,
 } from './saga';
 
 import { rootReducer } from '..';
@@ -793,4 +794,12 @@ describe('messages saga', () => {
       'the-third-message-id': { id: 'the-third-message-id', message: 'the third message' },
     });
   });
+
+  describe('getPreview', () => {
+    it('guards from empty messages (like when you upload a file)', () => {
+      const generator = getPreview(null);
+
+      expect(generator.next().value).toEqual(undefined);
+    });
+  });
 });

src/store/messages/saga.ts

@@ -339,7 +339,9 @@ export function* receiveNewMessage(action) {
   );
 }
 
-function* getPreview(message) {
+export function* getPreview(message) {
+  if (!message) return;
+
   const link: linkifyType[] = extractLink(message);
   if (!link.length) return;