fix(GuildMember): mark joined as nullable

src/structures/Guild.js

@@ -567,7 +567,8 @@ class Guild {
   fetchMember(user, cache = true) {
     user = this.client.resolver.resolveUser(user);
     if (!user) return Promise.reject(new Error('Invalid or uncached id provided.'));
-    if (this.members.has(user.id)) return Promise.resolve(this.members.get(user.id));
+    const member = this.members.get(user.id);
+    if (member && member.joinedTimestamp) return Promise.resolve(member);
     return this.client.rest.methods.getGuildMember(this, user, cache);
   }
 

src/structures/GuildMember.js

@@ -2,7 +2,7 @@ const TextBasedChannel = require('./interfaces/TextBasedChannel');
 const Role = require('./Role');
 const Permissions = require('../util/Permissions');
 const Collection = require('../util/Collection');
-const Presence = require('./Presence').Presence;
+const { Presence } = require('./Presence');
 const util = require('util');
 
 /**
@@ -31,6 +31,12 @@ class GuildMember {
      */
     this.user = {};
 
+    /**
+     * The timestamp this member joined the guild at
+     * @type {number}
+     */
+    this.joinedTimestamp = null;
+
     this._roles = [];
     if (data) this.setup(data);
 
@@ -96,11 +102,7 @@ class GuildMember {
      */
     this.nickname = data.nick || null;
 
-    /**
+    if (data.joined_at) this.joinedTimestamp = new Date(data.joined_at).getTime();
-     * The timestamp this member joined the guild at
-     * @type {number}
-     */
-    this.joinedTimestamp = new Date(data.joined_at).getTime();
 
     this.user = data.user;
     this._roles = data.roles;
@@ -112,7 +114,7 @@ class GuildMember {
    * @readonly
    */
   get joinedAt() {
-    return new Date(this.joinedTimestamp);
+    return this.joinedTimestamp ? new Date(this.joinedTimestamp) : null;
   }
 
   /**