feat(client): createSupergroup method

packages/client/src/client.ts

@@ -16,6 +16,7 @@ import { start } from './methods/auth/start'
 import { addChatMembers } from './methods/chats/add-chat-members'
 import { archiveChats } from './methods/chats/archive-chats'
 import { createChannel } from './methods/chats/create-channel'
+import { createSupergroup } from './methods/chats/create-supergroup'
 import { deleteChannel } from './methods/chats/delete-channel'
 import { getChatPreview } from './methods/chats/get-chat-preview'
 import { getChat } from './methods/chats/get-chat'
@@ -365,6 +366,15 @@ export class TelegramClient extends BaseTelegramClient {
     createChannel(title: string, description?: string): Promise<Chat> {
         return createChannel.apply(this, arguments)
     }
+    /**
+     * Create a new supergroup
+     *
+     * @param title  Title of the supergroup
+     * @param description  (default: `''`) Description of the supergroup
+     */
+    createSupergroup(title: string, description?: string): Promise<Chat> {
+        return createSupergroup.apply(this, arguments)
+    }
 
     /**
      * Delete a channel or a supergroup

packages/client/src/methods/chats/create-supergroup.ts

@@ -0,0 +1,32 @@
+import { TelegramClient } from '../../client'
+import { Chat, MtCuteTypeAssertionError } from '../../types'
+
+/**
+ * Create a new supergroup
+ *
+ * @param title  Title of the supergroup
+ * @param description  Description of the supergroup
+ * @internal
+ */
+export async function createSupergroup(
+    this: TelegramClient,
+    title: string,
+    description = ''
+): Promise<Chat> {
+    const res = await this.call({
+        _: 'channels.createChannel',
+        title,
+        about: description,
+        megagroup: true
+    })
+
+    if (!(res._ === 'updates' || res._ === 'updatesCombined')) {
+        throw new MtCuteTypeAssertionError(
+            'createChannel (@ channels.createChannel)',
+            'updates | updatesCombined',
+            res._
+        )
+    }
+
+    return new Chat(this, res.chats[0])
+}