quick fix

client/js/chat-client.js

@@ -63,6 +63,10 @@ export class ChatApp extends DtpApp {
       this.emojiPicker.addEventListener('emoji-click', this.onEmojiPicked.bind(this));
     }
 
+    this.pendingFiles = {
+      images: [ ],
+      videos: [ ],
+    };
     this.dragFeedback = document.querySelector('.dtp-drop-feedback');
 
     window.addEventListener('dtp-load', this.onDtpLoad.bind(this));
@@ -274,7 +278,7 @@ export class ChatApp extends DtpApp {
 
     // set focus back to chat input
     this.chat.imageFiles.value = null;
-    this.chat.videoFile = null;
+    this.chat.videoFile.value = null;
     this.chat.input.focus();
 
     this.chat.sendButton.setAttribute('disabled', '');
@@ -365,7 +369,9 @@ export class ChatApp extends DtpApp {
   async onChatMessage (message) {
     const isAtBottom = this.chat.isAtBottom;
     this.chat.messageList.insertAdjacentHTML('beforeend', message.html);
-    this.audio.playSound(ChatApp.SFX_CHAT_MESSAGE);
+    if (!this.haveFocus) {
+      this.audio.playSound(ChatApp.SFX_CHAT_MESSAGE);
+    }
     this.scrollChatToBottom(isAtBottom);
 
     if (!this.haveFocus && (this.notificationPermission === 'granted')) {