Add User.lastMessage, GuildMember.lastMessage and TextBasedChannel.lastMessage (#1135)

* Add User.lastMessage

* User.lastMessage and GuildMember.lastMessage

* User, GuildMember and TextBasedChannel lastMessage

* Update MessageCreate.js

src/client/actions/MessageCreate.js

@@ -14,17 +14,32 @@ class MessageCreateAction extends Action {
         for (let i = 0; i < data.length; i++) {
           messages[i] = channel._cacheMessage(new Message(channel, data[i], client));
         }
-        channel.lastMessageID = messages[messages.length - 1].id;
-        if (user) user.lastMessageID = messages[messages.length - 1].id;
-        if (member) member.lastMessageID = messages[messages.length - 1].id;
+        const lastMessage = messages[messages.length - 1];
+        channel.lastMessageID = lastMessage.id;
+        channel.lastMessage = lastMessage;
+        if (user) {
+          user.lastMessageID = lastMessage.id;
+          user.lastMessage = lastMessage;
+        }
+        if (member) {
+          member.lastMessageID = lastMessage.id;
+          member.lastMessage = lastMessage;
+        }
         return {
           messages,
         };
       } else {
         const message = channel._cacheMessage(new Message(channel, data, client));
         channel.lastMessageID = data.id;
-        if (user) user.lastMessageID = data.id;
-        if (member) member.lastMessageID = data.id;
+        channel.lastMessage = message;
+        if (user) {
+          user.lastMessageID = data.id;
+          user.lastMessage = message;
+        }
+        if (member) {
+          member.lastMessageID = data.id;
+          member.lastMessage = message;
+        }
         return {
           message,
         };

src/structures/GuildMember.js

@@ -39,6 +39,12 @@ class GuildMember {
      * @type {?Snowflake}
      */
     this.lastMessageID = null;
+
+    /**
+     * The Message object of the last message sent by the member in their guild, if one was sent.
+     * @type {?Message}
+     */
+    this.lastMessage = null;
   }
 
   setup(data) {

src/structures/User.js

@@ -55,6 +55,12 @@ class User {
      * @type {?Snowflake}
      */
     this.lastMessageID = null;
+
+    /**
+     * The Message object of the last message sent by the user, if one was sent.
+     * @type {?Message}
+     */
+    this.lastMessage = null;
   }
 
   patch(data) {

src/structures/interface/TextBasedChannel.js

@@ -20,6 +20,12 @@ class TextBasedChannel {
      * @type {?Snowflake}
      */
     this.lastMessageID = null;
+
+    /**
+     * The Message object of the last message in the channel, if one was sent.
+     * @type {?Message}
+     */
+    this.lastMessage = null;
   }
 
   /**