feat(Partials): add DMChannel/MessageReaction#fetch() and Parti… (#3261)

* add DMChannel#fetch() & Action#getChannel({recipients})

* ref for MessageReaction partial

* typings

* add PartialTypes.REACTION

* accommodate for fully removed reactions

* fix incorrect wording and typo

* typings: MessageReaction#count is nullable

* typings: mark MessageReaction#partial as readonly

Co-Authored-By: Vlad Frangu <kingdgrizzle@gmail.com>

* fix(User): fetch dm channel if cached one is partial

* docs: add missing comma

Co-Authored-By: Antonio Román <kyradiscord@gmail.com>

src/structures/DMChannel.js

@@ -56,7 +56,15 @@ class DMChannel extends Channel {
    * @readonly
    */
   get partial() {
-    return !this.recipient;
+    return this.lastMessageID === undefined;
+  }
+
+  /**
+   * Fetch this DMChannel.
+   * @returns {Promise<DMChannel>}
+   */
+  fetch() {
+    return this.recipient.createDM();
   }
 
   /**

src/structures/MessageReaction.js

@@ -27,12 +27,6 @@ class MessageReaction {
      */
     this.me = data.me;
 
-    /**
-     * The number of people that have given the same reaction
-     * @type {number}
-     */
-    this.count = data.count || 0;
-
     /**
      * The users that have given this reaction, mapped by their ID
      * @type {ReactionUserStore<Snowflake, User>}
@@ -40,6 +34,16 @@ class MessageReaction {
     this.users = new ReactionUserStore(client, undefined, this);
 
     this._emoji = new ReactionEmoji(this, data.emoji);
+
+    this._patch(data);
+  }
+
+  _patch(data) {
+    /**
+     * The number of people that have given the same reaction
+     * @type {?number}
+     */
+    this.count = typeof data.count === 'number' ? data.count : null;
   }
 
   /**
@@ -63,18 +67,36 @@ class MessageReaction {
     return this._emoji;
   }
 
+  /**
+   * Whether or not this reaction is a partial
+   * @type {boolean}
+   * @readonly
+   */
+  get partial() {
+    return this.count === null;
+  }
+
+  /**
+   * Fetch this reaction.
+   * @returns {Promise<MessageReaction>}
+   */
+  fetch() {
+    return this.message.reactions._fetchReaction(this.emoji, true);
+  }
 
   toJSON() {
     return Util.flatten(this, { emoji: 'emojiID', message: 'messageID' });
   }
 
   _add(user) {
+    if (this.partial) return;
     this.users.set(user.id, user);
     if (!this.me || user.id !== this.message.client.user.id || this.count === 0) this.count++;
     if (!this.me) this.me = user.id === this.message.client.user.id;
   }
 
   _remove(user) {
+    if (this.partial) return;
     this.users.delete(user.id);
     if (!this.me || user.id !== this.message.client.user.id) this.count--;
     if (user.id === this.message.client.user.id) this.me = false;

src/structures/User.js

@@ -211,7 +211,7 @@ class User extends Base {
    */
   async createDM() {
     const { dmChannel } = this;
-    if (dmChannel) return dmChannel;
+    if (dmChannel && !dmChannel.partial) return dmChannel;
     const data = await this.client.api.users(this.client.user.id).channels.post({ data: {
       recipient_id: this.id,
     } });