feat(Channel): Add isThreadOnly()

#9847 backport

src/structures/Channel.js

@@ -12,6 +12,7 @@ let ThreadChannel;
 let VoiceChannel;
 let DirectoryChannel;
 let ForumChannel;
+let MediaChannel;
 const ChannelFlags = require('../util/ChannelFlags');
 const { ChannelTypes, ThreadChannelTypes, VoiceBasedChannelTypes } = require('../util/Constants');
 const SnowflakeUtil = require('../util/SnowflakeUtil');
@@ -177,6 +178,14 @@ class Channel extends Base {
     return ThreadChannelTypes.includes(this.type);
   }
 
+  /**
+   * Indicates whether this channel is {@link ThreadOnlyChannel}.
+   * @returns {boolean}
+   */
+  isThreadOnly() {
+    return 'availableTags' in this;
+  }
+
   /**
    * Indicates whether this channel is a {@link DirectoryChannel}
    * @returns {boolean}
@@ -196,6 +205,7 @@ class Channel extends Base {
     VoiceChannel ??= require('./VoiceChannel');
     DirectoryChannel ??= require('./DirectoryChannel');
     ForumChannel ??= require('./ForumChannel');
+    MediaChannel ??= require('./MediaChannel');
 
     let channel;
     if (!data.guild_id && !guild) {
@@ -249,6 +259,10 @@ class Channel extends Base {
           case ChannelTypes.GUILD_FORUM:
             channel = new ForumChannel(guild, data, client);
             break;
+
+          case ChannelTypes.GUILD_MEDIA:
+            channel = new MediaChannel(guild, data, client);
+            break;
         }
         if (channel && !allowUnknownGuild) guild.channels?.cache.set(channel.id, channel);
       }

typings/index.d.ts

@@ -730,6 +730,7 @@ export abstract class Channel extends Base {
   public isVoice(): this is BaseGuildVoiceChannel;
   public isThread(): this is ThreadChannel;
   public isDirectory(): this is DirectoryChannel;
+  public isThreadOnly(): this is ThreadOnlyChannel;
   public toString(): ChannelMention;
 }