reset number of posts to fetch on channel switch and fresh page load

web/react/utils/async_client.jsx

@@ -272,17 +272,20 @@ module.exports.search = function(terms) {
     );
 }
 
-module.exports.getPosts = function(force, id) {
+module.exports.getPosts = function(force, id, maxPosts) {
     if (PostStore.getCurrentPosts() == null || force) {
         var channelId = id ? id : ChannelStore.getCurrentId();
 
         if (isCallInProgress("getPosts_"+channelId)) return;
 
         var post_list = PostStore.getCurrentPosts();
+
+        if (!maxPosts) { maxPosts = Constants.POST_CHUNK_SIZE * Constants.MAX_POST_CHUNKS };
+
         // if we already have more than POST_CHUNK_SIZE posts,
         //   let's get the amount we have but rounded up to next multiple of POST_CHUNK_SIZE,
-        //   with a max at 180
-        var numPosts = post_list && post_list.order.length > 0 ? Math.min(180, Constants.POST_CHUNK_SIZE * Math.ceil(post_list.order.length / Constants.POST_CHUNK_SIZE)) : Constants.POST_CHUNK_SIZE;
+        //   with a max at maxPosts
+        var numPosts = post_list && post_list.order.length > 0 ? Math.min(maxPosts, Constants.POST_CHUNK_SIZE * Math.ceil(post_list.order.length / Constants.POST_CHUNK_SIZE)) : Constants.POST_CHUNK_SIZE;
 
         if (channelId != null) {
             callTracker["getPosts_"+channelId] = utils.getTimestamp();