feat(GuildChannelManager): add .addFollower() method (#8567)

* feat(GuildChannelManager): add `.addFollower()` method

* docs: dpply suggestions

Co-authored-by: Jiralite <33201955+Jiralite@users.noreply.github.com>

* fix: resolve from `GuildChannelManager`

Co-authored-by: Jiralite <33201955+Jiralite@users.noreply.github.com>

* types: correct channel type

* docs: update description

Co-authored-by: A. Román <kyradiscord@gmail.com>

* docs: update description

Co-authored-by: A. Román <kyradiscord@gmail.com>

Co-authored-by: Jiralite <33201955+Jiralite@users.noreply.github.com>
Co-authored-by: A. Román <kyradiscord@gmail.com>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/discord.js/src/managers/GuildChannelManager.js

@@ -98,6 +98,24 @@ class GuildChannelManager extends CachedManager {
     return super.resolveId(channel);
   }
 
+  /**
+   * Adds the target channel to a channel's followers.
+   * @param {NewsChannel|Snowflake} channel The channel to follow
+   * @param {TextChannelResolvable} targetChannel The channel where published announcements will be posted at
+   * @param {string} [reason] Reason for creating the webhook
+   * @returns {Promise<Snowflake>} Returns created target webhook id.
+   */
+  async addFollower(channel, targetChannel, reason) {
+    const channelId = this.resolveId(channel);
+    const targetChannelId = this.resolveId(targetChannel);
+    if (!channelId || !targetChannelId) throw new Error(ErrorCodes.GuildChannelResolve);
+    const { webhook_id } = await this.client.rest.post(Routes.channelFollowers(channelId), {
+      body: { webhook_channel_id: targetChannelId },
+      reason,
+    });
+    return webhook_id;
+  }
+
   /**
    * Options used to create a new channel in a guild.
    * @typedef {CategoryCreateChannelOptions} GuildChannelCreateOptions

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

@@ -3457,6 +3457,11 @@ export class GuildChannelManager extends CachedManager<Snowflake, GuildBasedChan
   public get channelCountWithoutThreads(): number;
   public guild: Guild;
 
+  public addFollower(
+    channel: NewsChannel | Snowflake,
+    targetChannel: TextChannelResolvable,
+    reason?: string,
+  ): Promise<Snowflake>;
   public create<T extends GuildChannelTypes>(
     options: GuildChannelCreateOptions & { type: T },
   ): Promise<MappedGuildChannelTypes[T]>;