feat(MessageReaction): add remove method and Client#messageReactionRemoveEmoji (#3723)

* Add support for MessageReaction#remove and MESSAGE_REACTION_REMOVE_EMOJI

* Remove reaction from cache

Co-Authored-By: matthewfripp <50251454+matthewfripp@users.noreply.github.com>

* fix: message may be partial

* Clarify what the event entails

* Document client in MessageReaction

Co-Authored-By: SpaceEEC <spaceeec@yahoo.com>

* await the REST call

* Add MessageReaction#remove to typings

Co-authored-by: matthewfripp <50251454+matthewfripp@users.noreply.github.com>
Co-authored-by: SpaceEEC <spaceeec@yahoo.com>

src/client/actions/Action.js

@@ -54,7 +54,7 @@ class GenericAction {
     return this.getPayload({
       emoji: data.emoji,
       count: message.partial ? null : 0,
-      me: user.id === this.client.user.id,
+      me: user ? user.id === this.client.user.id : false,
     }, message.reactions, id, PartialTypes.REACTION);
   }
 

src/client/actions/ActionsManager.js

@@ -11,6 +11,7 @@ class ActionsManager {
     this.register(require('./MessageReactionAdd'));
     this.register(require('./MessageReactionRemove'));
     this.register(require('./MessageReactionRemoveAll'));
+    this.register(require('./MessageReactionRemoveEmoji'));
     this.register(require('./ChannelCreate'));
     this.register(require('./ChannelDelete'));
     this.register(require('./ChannelUpdate'));

src/client/actions/MessageReactionRemoveEmoji.js

@@ -0,0 +1,28 @@
+'use strict';
+
+const Action = require('./Action');
+const { Events } = require('../../util/Constants');
+
+class MessageReactionRemoveEmoji extends Action {
+  handle(data) {
+    const channel = this.getChannel(data);
+    if (!channel || channel.type === 'voice') return false;
+
+    const message = this.getMessage(data, channel);
+    if (!message) return false;
+
+    const reaction = this.getReaction(data, message);
+    if (!reaction) return false;
+    if (!message.partial) message.reactions.delete(reaction.emoji.id || reaction.emoji.name);
+
+    /**
+     * Emitted when a bot removes an emoji reaction from a cached message.
+     * @event Client#messageReactionRemoveEmoji
+     * @param {MessageReaction} reaction The reaction that was removed
+     */
+    this.client.emit(Events.MESSAGE_REACTION_REMOVE_EMOJI, reaction);
+    return { reaction };
+  }
+}
+
+module.exports = MessageReactionRemoveEmoji;

src/client/websocket/handlers/MESSAGE_REACTION_REMOVE_EMOJI.js

@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = (client, packet) => {
+  client.actions.MessageReactionRemoveEmoji.handle(packet.d);
+};

src/structures/MessageReaction.js

@@ -15,6 +15,13 @@ class MessageReaction {
    * @param {Message} message The message the reaction refers to
    */
   constructor(client, data, message) {
+    /**
+     * The client that instantiated this message reaction
+     * @name MessageReaction#client
+     * @type {Client}
+     * @readonly
+     */
+    Object.defineProperty(this, 'client', { value: client });
     /**
      * The message that this reaction refers to
      * @type {Message}
@@ -47,6 +54,16 @@ class MessageReaction {
     if (this.count == undefined) this.count = data.count;
   }
 
+  /**
+   * Removes all users from this reaction.
+   * @returns {Promise<MessageReaction>}
+   */
+  async remove() {
+    await this.client.api.channels(this.message.channel.id).messages(this.message.id).reactions(this._emoji.identifier)
+      .delete();
+    return this;
+  }
+
   /**
    * The emoji of this reaction, either an GuildEmoji object for known custom emojis, or a ReactionEmoji
    * object which has fewer properties. Whatever the prototype of the emoji, it will still have

src/util/Constants.js

@@ -262,6 +262,7 @@ exports.Events = {
   MESSAGE_REACTION_ADD: 'messageReactionAdd',
   MESSAGE_REACTION_REMOVE: 'messageReactionRemove',
   MESSAGE_REACTION_REMOVE_ALL: 'messageReactionRemoveAll',
+  MESSAGE_REACTION_REMOVE_EMOJI: 'messageReactionRemoveEmoji',
   USER_UPDATE: 'userUpdate',
   PRESENCE_UPDATE: 'presenceUpdate',
   VOICE_SERVER_UPDATE: 'voiceServerUpdate',
@@ -379,6 +380,7 @@ exports.WSEvents = keyMirror([
   'MESSAGE_REACTION_ADD',
   'MESSAGE_REACTION_REMOVE',
   'MESSAGE_REACTION_REMOVE_ALL',
+  'MESSAGE_REACTION_REMOVE_EMOJI',
   'USER_UPDATE',
   'PRESENCE_UPDATE',
   'TYPING_START',