src: support new message fields (#3388)

* src: Update channel pattern

* src: Remove useless non-capture group

* src: it's as though we're starting fresh

* src: Bring this up to date for reals now

* src: typings and a bug fix

* src: Add crossposted channels to message mentions

* src: Requested changes and add typings

* src: Move Object.keys outside loop

* typings: Fix enum being exported when it shouldn't

* src: Consistency with roles and users

* docs: Correct docstring for MessageFlags#flags

* docs: Correct docstring for MessageMentions#crosspostedChannels

* docs: Suggestions
Co-authored-by: SpaceEEC

* src: Reset flags to 0 if no flags are received on MESSAGE_UPDATE

src/structures/Message.js

@@ -13,6 +13,7 @@ const Permissions = require('../util/Permissions');
 const Base = require('./Base');
 const { Error, TypeError } = require('../errors');
 const APIMessage = require('./APIMessage');
+const MessageFlags = require('../util/MessageFlags');
 
 /**
  * Represents a message on Discord.
@@ -81,7 +82,9 @@ class Message extends Base {
 
     /**
      * A random number or string used for checking message delivery
-     * @type {string}
+     * <warn>This is only received after the message was sent successfully, and
+     * lost if re-fetched</warn>
+     * @type {?string}
      */
     this.nonce = data.nonce;
 
@@ -89,7 +92,7 @@ class Message extends Base {
      * Whether or not this message was sent by Discord, not actually a user (e.g. pin notifications)
      * @type {boolean}
      */
-    this.system = data.type === 6;
+    this.system = data.type !== 0;
 
     /**
      * A list of embeds in the message - e.g. YouTube Player
@@ -137,7 +140,7 @@ class Message extends Base {
      * All valid mentions that the message contains
      * @type {MessageMentions}
      */
-    this.mentions = new Mentions(this, data.mentions, data.mention_roles, data.mention_everyone);
+    this.mentions = new Mentions(this, data.mentions, data.mention_roles, data.mention_everyone, data.mention_channels);
 
     /**
      * ID of the webhook that sent the message, if applicable
@@ -172,6 +175,30 @@ class Message extends Base {
     } else if (data.member && this.guild && this.author) {
       this.guild.members.add(Object.assign(data.member, { user: this.author }));
     }
+
+    /**
+     * Flags that are applied to the message
+     * @type {Readonly<MessageFlags>}
+     */
+    this.flags = new MessageFlags(data.flags).freeze();
+
+    /**
+     * Reference data sent in a crossposted message.
+     * @typedef {Object} MessageReference
+     * @property {string} channelID ID of the channel the message was crossposted from
+     * @property {?string} guildID ID of the guild the message was crossposted from
+     * @property {?string} messageID ID of the message that was crossposted
+     */
+
+    /**
+     * Message reference data
+     * @type {?MessageReference}
+     */
+    this.reference = data.message_reference ? {
+      channelID: data.message_reference.channel_id,
+      guildID: data.message_reference.guild_id,
+      messageID: data.message_reference.message_id,
+    } : null;
   }
 
   /**
@@ -214,8 +241,11 @@ class Message extends Base {
       this,
       'mentions' in data ? data.mentions : this.mentions.users,
       'mentions_roles' in data ? data.mentions_roles : this.mentions.roles,
-      'mention_everyone' in data ? data.mention_everyone : this.mentions.everyone
+      'mention_everyone' in data ? data.mention_everyone : this.mentions.everyone,
+      'mention_channels' in data ? data.mention_channels : this.mentions.crosspostedChannels
     );
+
+    this.flags = new MessageFlags('flags' in data ? data.flags : 0).freeze();
   }
 
   /**

src/structures/MessageMentions.js

@@ -3,12 +3,13 @@
 const Collection = require('../util/Collection');
 const Util = require('../util/Util');
 const GuildMember = require('./GuildMember');
+const { ChannelTypes } = require('../util/Constants');
 
 /**
  * Keeps track of mentions in a {@link Message}.
  */
 class MessageMentions {
-  constructor(message, users, roles, everyone) {
+  constructor(message, users, roles, everyone, crosspostedChannels) {
     /**
      * The client the message is from
      * @type {Client}
@@ -86,6 +87,39 @@ class MessageMentions {
      * @private
      */
     this._channels = null;
+
+    /**
+     * Crossposted channel data.
+     * @typedef {Object} CrosspostedChannel
+     * @property {string} channelID ID of the mentioned channel
+     * @property {string} guildID ID of the guild that has the channel
+     * @property {string} type Type of the channel
+     * @property {string} name The name of the channel
+     */
+
+    if (crosspostedChannels) {
+      if (crosspostedChannels instanceof Collection) {
+        /**
+         * A collection of crossposted channels
+         * @type {Collection<Snowflake, CrosspostedChannel>}
+         */
+        this.crosspostedChannels = new Collection(crosspostedChannels);
+      } else {
+        this.crosspostedChannels = new Collection();
+        const channelTypes = Object.keys(ChannelTypes);
+        for (const d of crosspostedChannels) {
+          const type = channelTypes[d.type];
+          this.crosspostedChannels.set(d.id, {
+            channelID: d.id,
+            guildID: d.guild_id,
+            type: type ? type.toLowerCase() : 'unknown',
+            name: d.name,
+          });
+        }
+      }
+    } else {
+      this.crosspostedChannels = new Collection();
+    }
   }
 
   /**