refactor: move member adding to manager (#6231)

Co-authored-by: Vlad Frangu <kingdgrizzle@gmail.com>
Co-authored-by: Antonio Román <kyradiscord@gmail.com>
Co-authored-by: Sugden <28943913+NotSugden@users.noreply.github.com>

typings/index.ts

@@ -404,6 +404,9 @@ client.on('ready', async () => {
   });
 });
 
+// This is to check that stuff is the right type
+declare const assertIsPromiseMember: (m: Promise<GuildMember>) => void;
+
 client.on('guildCreate', g => {
   const channel = g.channels.cache.random();
   if (!channel) return;
@@ -411,6 +414,32 @@ client.on('guildCreate', g => {
   channel.setName('foo').then(updatedChannel => {
     console.log(`New channel name: ${updatedChannel.name}`);
   });
+
+  // @ts-expect-error no options
+  assertIsPromiseMember(g.members.add(testUserId));
+
+  // @ts-expect-error no access token
+  assertIsPromiseMember(g.members.add(testUserId, {}));
+
+  // @ts-expect-error invalid role resolvable
+  assertIsPromiseMember(g.members.add(testUserId, { accessToken: 'totallyRealAccessToken', roles: [g.roles.cache] }));
+
+  assertType<Promise<GuildMember | null>>(
+    g.members.add(testUserId, { accessToken: 'totallyRealAccessToken', fetchWhenExisting: false }),
+  );
+
+  assertIsPromiseMember(g.members.add(testUserId, { accessToken: 'totallyRealAccessToken' }));
+
+  assertIsPromiseMember(
+    g.members.add(testUserId, {
+      accessToken: 'totallyRealAccessToken',
+      mute: true,
+      deaf: false,
+      roles: [g.roles.cache.first()!],
+      force: true,
+      fetchWhenExisting: true,
+    }),
+  );
 });
 
 client.on('messageReactionRemoveAll', async message => {