feat(BaseChannel): Add isThreadOnly()

packages/discord.js/src/structures/BaseChannel.js

@@ -147,6 +147,14 @@ class BaseChannel extends Base {
     return 'bitrate' in this;
   }
 
+  /**
+   * Indicates whether this channel is {@link ThreadOnlyChannel thread-only}.
+   * @returns {boolean}
+   */
+  isThreadOnly() {
+    return 'availableTags' in this;
+  }
+
   toJSON(...props) {
     return super.toJSON({ createdTimestamp: true }, ...props);
   }

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

@@ -942,6 +942,7 @@ export abstract class BaseChannel extends Base {
   public isTextBased(): this is TextBasedChannel;
   public isDMBased(): this is PartialGroupDMChannel | DMChannel | PartialDMChannel;
   public isVoiceBased(): this is VoiceBasedChannel;
+  public isThreadOnly(): this is ThreadOnlyChannel;
   public toString(): ChannelMention | UserMention;
 }