MM-15700 Manual load more trigger in virt list does not load more mes…

…sages (mattermost#2824)

* MM-15700 Manual load more trigger in virt list does not load more messages

  * Exclude MANUAL_TRIGGER_LOAD_MESSAGES from getLastPostId

* Change condition to be a new func

utils/post_utils.jsx

@@ -225,18 +225,23 @@ export function isErrorInvalidSlashCommand(error) {
  return false;
 }
 
+function isIdNotPost(postId) {
+ return (
+ PostListUtils.isStartOfNewMessages(postId) ||
+ PostListUtils.isDateLine(postId) ||
+ postId === PostListRowListIds.CHANNEL_INTRO_MESSAGE ||
+ postId === PostListRowListIds.MORE_MESSAGES_LOADER ||
+ postId === PostListRowListIds.MANUAL_TRIGGER_LOAD_MESSAGES
+ );
+}
+
 // getLastPostId returns the most recent post ID in the given list of post IDs. This function is copied from
 // mattermost-redux, except it also includes additional special IDs that are only used in the web app.
 export function getLastPostId(postIds) {
  for (let i = postIds.length - 1; i >= 0; i--) {
  const item = postIds[i];
 
- if (
- PostListUtils.isStartOfNewMessages(item) ||
- PostListUtils.isDateLine(item) ||
- item === PostListRowListIds.CHANNEL_INTRO_MESSAGE ||
- item === PostListRowListIds.MORE_MESSAGES_LOADER
- ) {
+ if (isIdNotPost(item)) {
  // This is not a post at all
  continue;
  }

utils/post_utils.test.jsx

@@ -4,6 +4,7 @@
 import assert from 'assert';
 
 import * as PostUtils from 'utils/post_utils.jsx';
+import {PostListRowListIds} from 'utils/constants.jsx';
 
 describe('PostUtils.containsAtChannel', () => {
  test('should return correct @all (same for @channel)', () => {
@@ -524,3 +525,30 @@ describe('PostUtils.postMessageOnKeyPress', () => {
  });
  }
 });
+
+describe('PostUtils.getLastPostId', () => {
+ test('Should not return MANUAL_TRIGGER_LOAD_MESSAGES', () => {
+ const postId = PostUtils.getLastPostId(['postId1', 'postId2', PostListRowListIds.MANUAL_TRIGGER_LOAD_MESSAGES]);
+ assert.equal(postId, 'postId2');
+ });
+
+ test('Should not return MORE_MESSAGES_LOADER', () => {
+ const postId = PostUtils.getLastPostId(['postId1', 'postId2', PostListRowListIds.MORE_MESSAGES_LOADER]);
+ assert.equal(postId, 'postId2');
+ });
+
+ test('Should not return CHANNEL_INTRO_MESSAGE', () => {
+ const postId = PostUtils.getLastPostId(['postId1', 'postId2', PostListRowListIds.CHANNEL_INTRO_MESSAGE]);
+ assert.equal(postId, 'postId2');
+ });
+
+ test('Should not return dateline', () => {
+ const postId = PostUtils.getLastPostId(['postId1', 'postId2', 'date-1558290600000']);
+ assert.equal(postId, 'postId2');
+ });
+
+ test('Should not return START_OF_NEW_MESSAGES', () => {
+ const postId = PostUtils.getLastPostId(['postId1', 'postId2', PostListRowListIds.START_OF_NEW_MESSAGES]);
+ assert.equal(postId, 'postId2');
+ });
+});