fix: ensure VIEW_CHANNEL permissions before trying to join (#3046)

* fix: ensure VIEW_CHANNEL permissions before joining

* nit(GuildChannel): remove the redundant truthy check

src/structures/GuildChannel.js

@@ -523,10 +523,21 @@ class GuildChannel extends Channel {
    * @readonly
    */
   get manageable() {
+    if (this.client.user.id === this.guild.ownerID) return true;
+    if (!this.viewable) return false;
+    return this.permissionsFor(this.client.user).has(Permissions.FLAGS.MANAGE_CHANNELS, false);
+  }
+
+  /**
+   * Whether the channel is viewable by the client user
+   * @type {boolean}
+   * @readonly
+   */
+  get viewable() {
     if (this.client.user.id === this.guild.ownerID) return true;
     const permissions = this.permissionsFor(this.client.user);
     if (!permissions) return false;
-    return permissions.has([Permissions.FLAGS.MANAGE_CHANNELS, Permissions.FLAGS.VIEW_CHANNEL], false);
+    return permissions.has(Permissions.FLAGS.VIEW_CHANNEL, false);
   }
 
   /**

src/structures/VoiceChannel.js

@@ -71,14 +71,15 @@ class VoiceChannel extends GuildChannel {
   }
 
   /**
-   * Checks if the client has permission join the voice channel
+   * Whether the channel is joinable by the client user
    * @type {boolean}
    * @readonly
    */
   get joinable() {
     if (browser) return false;
-    if (!this.permissionsFor(this.client.user).has('CONNECT', false)) return false;
+    if (!this.viewable) return false;
-    if (this.full && !this.permissionsFor(this.client.user).has('MOVE_MEMBERS', false)) return false;
+    if (!this.permissionsFor(this.client.user).has(Permissions.FLAGS.CONNECT, false)) return false;
+    if (this.full && !this.permissionsFor(this.client.user).has(Permissions.FLAGS.MOVE_MEMBERS, false)) return false;
     return true;
   }
 

typings/index.d.ts

@@ -523,6 +523,7 @@ declare module 'discord.js' {
 		public readonly permissionsLocked: boolean;
 		public readonly position: number;
 		public rawPosition: number;
+		public readonly viewable: boolean;
 		public clone(options?: GuildChannelCloneOptions): Promise<GuildChannel>;
 		public createInvite(options?: InviteOptions): Promise<Invite>;
 		public createOverwrite(userOrRole: RoleResolvable | UserResolvable, options: PermissionOverwriteOption, reason?: string): Promise<GuildChannel>;