fix: handle start=0 stop=0 for topics.getTopicPosts

add more tests

public/src/client/topic/posts.js

@@ -261,7 +261,7 @@ define('forum/topic/posts', [
 
 		infinitescroll.loadMore('topics.loadMore', {
 			tid: tid,
-			after: after,
+			after: after + (direction > 0 ? 1 : 0),
 			count: config.postsPerPage,
 			direction: direction,
 			topicPostSort: config.topicPostSort,

src/socket.io/topics/infinitescroll.js

@@ -30,9 +30,7 @@ module.exports = function (SocketTopics) {
 			parseInt(data.count, 10) || meta.config.postsPerPage || 20
 		));
 
-		if (data.direction === 1) {
-			start += 1;
-		} else if (data.direction === -1) {
+		if (data.direction === -1) {
 			start -= infScrollPostsPerPage;
 		}
 

src/topics/posts.js

@@ -39,7 +39,10 @@ module.exports = function (Topics) {
 				repliesStart -= 1;
 			}
 		}
-		const pids = await posts.getPidsFromSet(set, repliesStart, repliesStop, reverse);
+		let pids = [];
+		if (start !== 0 || stop !== 0) {
+			pids = await posts.getPidsFromSet(set, repliesStart, repliesStop, reverse);
+		}
 		if (!pids.length && !topicOrTid.mainPid) {
 			return [];
 		}

test/topics.js

@@ -507,6 +507,42 @@ describe('Topic\'s', () => {
 				const posts = await topics.getTopicPosts(null, `tid:${tid}:posts`, 0, 9, topic.userId, true);
 				assert.deepStrictEqual(posts, []);
 			});
+
+			it('should only return main post', async () => {
+				const topicData = await topics.getTopicData(tid);
+				const postsData = await topics.getTopicPosts(topicData, `tid:${tid}:posts`, 0, 0, topic.userId, false);
+				assert.strictEqual(postsData.length, 1);
+				assert.strictEqual(postsData[0].content, 'main post');
+			});
+
+			it('should only return first reply', async () => {
+				const topicData = await topics.getTopicData(tid);
+				const postsData = await topics.getTopicPosts(topicData, `tid:${tid}:posts`, 1, 1, topic.userId, false);
+				assert.strictEqual(postsData.length, 1);
+				assert.strictEqual(postsData[0].content, 'topic reply 1');
+			});
+
+			it('should return main post and first reply', async () => {
+				const topicData = await topics.getTopicData(tid);
+				const postsData = await topics.getTopicPosts(topicData, `tid:${tid}:posts`, 0, 1, topic.userId, false);
+				assert.strictEqual(postsData.length, 2);
+				assert.strictEqual(postsData[0].content, 'main post');
+				assert.strictEqual(postsData[1].content, 'topic reply 1');
+			});
+
+			it('should return posts in correct order', async () => {
+				const data = await socketTopics.loadMore({ uid: topic.userId }, { tid: tid, after: 20, direction: 1 });
+				assert.strictEqual(data.posts.length, 11);
+				assert.strictEqual(data.posts[0].content, 'topic reply 20');
+				assert.strictEqual(data.posts[1].content, 'topic reply 21');
+			});
+
+			it('should return posts in correct order in reverse direction', async () => {
+				const data = await socketTopics.loadMore({ uid: topic.userId }, { tid: tid, after: 25, direction: -1 });
+				assert.strictEqual(data.posts.length, 20);
+				assert.strictEqual(data.posts[0].content, 'topic reply 5');
+				assert.strictEqual(data.posts[1].content, 'topic reply 6');
+			});
 		});
 	});