feat(PartialGroupDMChannel): add missing ownerId property

packages/discord.js/src/errors/Messages.js

@@ -95,7 +95,8 @@ const Messages = {
   [DjsErrorCodes.ChannelNotCached]: 'Could not find the channel where this message came from in the cache!',
   [DjsErrorCodes.StageChannelResolve]: 'Could not resolve channel to a stage channel.',
   [DjsErrorCodes.GuildScheduledEventResolve]: 'Could not resolve the guild scheduled event.',
-  [DjsErrorCodes.FetchOwnerId]: type => `Couldn't resolve the ${type} ownerId to fetch the ${type} member.`,
+  [DjsErrorCodes.FetchOwnerId]: type =>
+    `Couldn't resolve the ${type} ownerId to fetch the ${type} ${type === 'group DM' ? 'owner' : 'member'}.`,
 
   [DjsErrorCodes.InvalidType]: (name, expected, an = false) => `Supplied ${name} is not a${an ? 'n' : ''} ${expected}.`,
   [DjsErrorCodes.InvalidElement]: (type, name, elem) => `Supplied ${type} ${name} includes an invalid element: ${elem}`,

packages/discord.js/src/structures/PartialGroupDMChannel.js

@@ -44,6 +44,16 @@ class PartialGroupDMChannel extends BaseChannel {
      * @type {PartialGroupDMMessageManager}
      */
     this.messages = new PartialGroupDMMessageManager(this);
+
+    if ('owner_id' in data) {
+      /**
+       * The user id of the owner of this Group DM Channel
+       * @type {?Snowflake}
+       */
+      this.ownerId = data.owner_id;
+    } else {
+      this.ownerId ??= null;
+    }
   }
 
   /**
@@ -55,6 +65,19 @@ class PartialGroupDMChannel extends BaseChannel {
     return this.icon && this.client.rest.cdn.channelIcon(this.id, this.icon, options);
   }
 
+  /**
+   * Fetches the owner of this Group DM Channel.
+   * @param {BaseFetchOptions} [options] The options for fetching the user
+   * @returns {Promise<User>}
+   */
+  async fetchOwner(options) {
+    if (!this.ownerId) {
+      throw new DiscordjsError(ErrorCodes.FetchOwnerId, 'group DM');
+    }
+
+    return this.client.users.fetch(this.ownerId, options);
+  }
+
   delete() {
     return Promise.reject(new DiscordjsError(ErrorCodes.DeleteGroupDMChannel));
   }

packages/discord.js/typings/index.d.ts

@@ -2558,7 +2558,9 @@ export class PartialGroupDMChannel extends BaseChannel {
   public icon: string | null;
   public recipients: PartialRecipient[];
   public messages: PartialGroupDMMessageManager;
+  public ownerId: Snowflake | null;
   public iconURL(options?: ImageURLOptions): string | null;
+  public fetchOwner(options?: BaseFetchOptions): Promise<User>;
   public toString(): ChannelMention;
 }