From c5cc58254990cf6feeeb40841c134d50527cbbcc Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Thu, 21 Jun 2018 10:23:55 +0800
Subject: [PATCH] FIX: Participants may not be in topic maps's attributes.

---
 app/assets/javascripts/discourse/widgets/topic-map.js.es6 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/app/assets/javascripts/discourse/widgets/topic-map.js.es6 b/app/assets/javascripts/discourse/widgets/topic-map.js.es6
index 00f22cbf65f..88da22a63ad 100644
--- a/app/assets/javascripts/discourse/widgets/topic-map.js.es6
+++ b/app/assets/javascripts/discourse/widgets/topic-map.js.es6
@@ -153,6 +153,7 @@ createWidget("topic-map-summary", {
     if (
       state.collapsed &&
       attrs.topicPostsCount > 2 &&
+      attrs.participants &&
       attrs.participants.length > 0
     ) {
       const participants = renderParticipants.call(