api: Make getMessages return full response

We use often use response processing functions to extract the
meaningful data out of a response. Previously we only cared about
the `messages` property.

Since the adding of `found_newest` and `found_oldest` fields we
now care about the whole response.

This reworks the `getMessages` to return the whole response and
any call to the function to use the `messages` property correctly.

Author: borisyankov

src/api/messages/getMessages.js

@@ -1,16 +1,26 @@
 /* @flow strict-local */
-import type { Auth, Message, Narrow } from '../apiTypes';
+import type { Auth, ApiResponseSuccess, Message, Narrow } from '../apiTypes';
 import { apiGet } from '../apiFetch';
 
+type ApiResponseMessages = {|
+  ...ApiResponseSuccess,
+  anchor: number,
+  found_anchor: boolean,
+  found_newest: boolean,
+  found_oldest: boolean,
+  messages: Message[],
+|};
+
+/** See https://zulipchat.com/api/get-messages */
 export default async (
   auth: Auth,
   narrow: Narrow,
   anchor: number,
   numBefore: number,
   numAfter: number,
   useFirstUnread: boolean = false,
-): Promise<Message[]> =>
-  apiGet(auth, 'messages', res => res.messages, {
+): Promise<ApiResponseMessages> =>
+  apiGet(auth, 'messages', (res: ApiResponseMessages): ApiResponseMessages => res, {
     narrow: JSON.stringify(narrow),
     anchor,
     num_before: numBefore,

src/message/fetchActions.js

@@ -74,7 +74,7 @@ export const fetchMessages = (
   useFirstUnread: boolean = false,
 ) => async (dispatch: Dispatch, getState: GetState) => {
   dispatch(messageFetchStart(narrow, numBefore, numAfter));
-  const messages = await getMessages(
+  const { messages } = await getMessages(
     getAuth(getState()),
     narrow,
     anchor,
@@ -183,7 +183,7 @@ export const fetchRestOfInitialData = () => async (dispatch: Dispatch, getState:
   const auth = getAuth(getState());
 
   timing.start('Rest of server data');
-  const [messages, streams] = await Promise.all([
+  const [{ messages }, streams] = await Promise.all([
     await tryUntilSuccessful(() =>
       getMessages(auth, ALL_PRIVATE_NARROW, LAST_MESSAGE_ANCHOR, 100, 0),
     ),

src/search/SearchMessagesCard.js

@@ -43,7 +43,7 @@ class SearchMessagesCard extends PureComponent<Props, State> {
 
     throttle(async () => {
       this.setState({ isFetching: true });
-      const messages = await getMessages(
+      const { messages } = await getMessages(
         auth,
         SEARCH_NARROW(query),
         LAST_MESSAGE_ANCHOR,