From 5a43acd42a1bc570611634b1e9c14abc35bb94d5 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Tue, 30 Jun 2020 19:51:28 -0600
Subject: [PATCH] Fix reaction event crashes in message previews

Fixes https://github.com/vector-im/riot-web/issues/14224
---
 src/stores/room-list/previews/ReactionEventPreview.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/stores/room-list/previews/ReactionEventPreview.ts b/src/stores/room-list/previews/ReactionEventPreview.ts
index d58f592feb..07fac107ca 100644
--- a/src/stores/room-list/previews/ReactionEventPreview.ts
+++ b/src/stores/room-list/previews/ReactionEventPreview.ts
@@ -22,8 +22,11 @@ import { _t } from "../../../languageHandler";
 
 export class ReactionEventPreview implements IPreview {
     public getTextFor(event: MatrixEvent, tagId?: TagID): string {
-        const reaction = event.getRelation().key;
-        if (!reaction) return;
+        const relation = event.getRelation();
+        if (!relation) return null; // invalid reaction (probably redacted)
+
+        const reaction = relation.key;
+        if (!reaction) return null; // invalid reaction (unknown format)
 
         if (isSelf(event) || !shouldPrefixMessagesIn(event.getRoomId(), tagId)) {
             return reaction;