fix: messageReactionRemove not emitting for partial messages (#3125)

src/client/actions/Action.js

@@ -43,6 +43,19 @@ class GenericAction {
       }) :
       channel.messages.get(id));
   }
+
+  getReaction(data, message, user) {
+    const emojiID = data.emoji.id || decodeURIComponent(data.emoji.name);
+    const existing = message.reactions.get(emojiID);
+    if (!existing && this.client.options.partials.includes(PartialTypes.MESSAGE)) {
+      return message.reactions.add({
+        emoji: data.emoji,
+        count: 0,
+        me: user.id === this.client.user.id,
+      });
+    }
+    return existing;
+  }
 }
 
 module.exports = GenericAction;

src/client/actions/MessageReactionAdd.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const Action = require('./Action');
+const { Events } = require('../../util/Constants');
 
 /*
 { user_id: 'id',
@@ -31,6 +32,14 @@ class MessageReactionAdd extends Action {
       me: user.id === this.client.user.id,
     });
     reaction._add(user);
+    /**
+     * Emitted whenever a reaction is added to a cached message.
+     * @event Client#messageReactionAdd
+     * @param {MessageReaction} messageReaction The reaction object
+     * @param {User} user The user that applied the guild or reaction emoji
+     */
+    this.client.emit(Events.MESSAGE_REACTION_ADD, reaction, user);
+
     return { message, reaction, user };
   }
 }

src/client/actions/MessageReactionRemove.js

@@ -26,8 +26,7 @@ class MessageReactionRemove extends Action {
     if (!message) return false;
 
     // Verify reaction
-    const emojiID = data.emoji.id || decodeURIComponent(data.emoji.name);
-    const reaction = message.reactions.get(emojiID);
+    const reaction = this.getReaction(data, message, user);
     if (!reaction) return false;
     reaction._remove(user);
     /**

src/client/websocket/handlers/MESSAGE_REACTION_ADD.js

@@ -1,14 +1,5 @@
 'use strict';
 
-const { Events } = require('../../../util/Constants');
-
 module.exports = (client, packet) => {
-  const { user, reaction } = client.actions.MessageReactionAdd.handle(packet.d);
-  /**
-   * Emitted whenever a reaction is added to a cached message.
-   * @event Client#messageReactionAdd
-   * @param {MessageReaction} messageReaction The reaction object
-   * @param {User} user The user that applied the guild or reaction emoji
-   */
-  if (reaction) client.emit(Events.MESSAGE_REACTION_ADD, reaction, user);
+  client.actions.MessageReactionAdd.handle(packet.d);
 };