feat(Guild): add systemChannelFlags (#3559)

* Add systemChannelFlags bitfield to Guild

* Implement @vladfrangu's suggestions

* fix: apply suggestions, reverse order of flags, reword docs

* docs: add SystemCHannelFlagsResolvable typedef

Co-authored-by: SpaceEEC <spaceeec@yahoo.com>

src/index.js

@@ -26,6 +26,7 @@ module.exports = {
   Snowflake: require('./util/Snowflake'),
   SnowflakeUtil: require('./util/Snowflake'),
   Structures: require('./util/Structures'),
+  SystemChannelFlags: require('./util/SystemChannelFlags'),
   Util: Util,
   util: Util,
   version: require('../package.json').version,

src/structures/Guild.js

@@ -10,6 +10,7 @@ const Collection = require('../util/Collection');
 const Util = require('../util/Util');
 const DataResolver = require('../util/DataResolver');
 const Snowflake = require('../util/Snowflake');
+const SystemChannelFlags = require('../util/SystemChannelFlags');
 const GuildMemberStore = require('../stores/GuildMemberStore');
 const RoleStore = require('../stores/RoleStore');
 const GuildEmojiStore = require('../stores/GuildEmojiStore');
@@ -275,6 +276,12 @@ class Guild extends Base {
     this.defaultMessageNotifications = DefaultMessageNotifications[data.default_message_notifications] ||
       data.default_message_notifications;
 
+    /**
+     * The value set for the guild's system channel flags
+     * @type {Readonly<SystemChannelFlags>}
+     */
+    this.systemChannelFlags = new SystemChannelFlags(data.system_channel_flags).freeze();
+
     /**
      * The maximum amount of members the guild can have
      * <info>You will need to fetch the guild using {@link Guild#fetch} if you want to receive this parameter</info>
@@ -773,6 +780,7 @@ class Guild extends Base {
    * @property {Base64Resolvable} [splash] The splash screen of the guild
    * @property {Base64Resolvable} [banner] The banner of the guild
    * @property {DefaultMessageNotifications|number} [defaultMessageNotifications] The default message notifications
+   * @property {SystemChannelFlagsResolvable} [systemChannelFlags] The system channel flags of the guild
    */
 
   /**
@@ -813,6 +821,9 @@ class Guild extends Base {
         DefaultMessageNotifications.indexOf(data.defaultMessageNotifications) :
         Number(data.defaultMessageNotifications);
     }
+    if (typeof data.systemChannelFlags !== 'undefined') {
+      _data.systemChannelFlags = SystemChannelFlags.resolve(data.systemChannelFlags);
+    }
     return this.client.api.guilds(this.id).patch({ data: _data, reason })
       .then(newData => this.client.actions.GuildUpdate.handle(newData).updated);
   }
@@ -839,6 +850,16 @@ class Guild extends Base {
   }
   /* eslint-enable max-len */
 
+  /**
+   * Edits the flags of the default message notifications of the guild.
+   * @param {SystemChannelFlagsResolvable} systemChannelFlags The new flags for the default message notifications
+   * @param {string} [reason] Reason for changing the flags of the default message notifications
+   * @returns {Promise<Guild>}
+   */
+  setSystemChannelFlags(systemChannelFlags, reason) {
+    return this.edit({ systemChannelFlags }, reason);
+  }
+
   /**
    * Edits the name of the guild.
    * @param {string} name The new name of the guild

src/util/SystemChannelFlags.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const BitField = require('./BitField');
+
+/**
+ * Data structure that makes it easy to interact with a {@link Guild#systemChannelFlags} bitfield.
+ * <info>Note that all event message types are enabled by default,
+ * and by setting their corresponding flags you are disabling them</info>
+ * @extends {BitField}
+ */
+class SystemChannelFlags extends BitField {
+  /**
+   * Data that can be resolved to give a sytem channel flag bitfield. This can be:
+   * * A string (see {@link SystemChannelFlags.FLAGS})
+   * * A sytem channel flag
+   * * An instance of SystemChannelFlags
+   * * An Array of SystemChannelFlagsResolvable
+   * @typedef {string|number|SystemChannelFlags|SystemChannelFlagsResolvable[]} SystemChannelFlagsResolvable
+   */
+}
+
+/**
+ * Numeric system channel flags. All available properties:
+ * * `WELCOME_MESSAGE_DISABLED`
+ * * `BOOST_MESSAGE_DISABLED`
+ * @type {Object}
+ */
+SystemChannelFlags.FLAGS = {
+  WELCOME_MESSAGE_DISABLED: 1 << 0,
+  BOOST_MESSAGE_DISABLED: 1 << 1,
+};
+
+module.exports = SystemChannelFlags;