start adding validation

src/managers/BaseCacheManager.js

@@ -1,5 +1,6 @@
 import hashjs from "hash.js";
 import { GLUON_VERSION, NAME, TO_JSON_TYPES_ENUM } from "../constants.js";
+import Client from "../Client.js";
 
 /**
  * The base cache manager for all cache managers.
@@ -20,6 +21,11 @@ class BaseCacheManager {
    * @constructor
    */
   constructor(client, { structureType } = {}) {
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be an instance of Client.");
+    if (!structureType)
+      throw new TypeError("GLUON: Structure type must be provided.");
+
     /**
      * The cache for this manager.
      * @type {Map<String, Object>}

src/managers/ChannelMessageManager.js

@@ -23,6 +23,10 @@ class ChannelMessageManager extends BaseCacheManager {
    */
   constructor(client, guild, channel) {
     super(client, { structureType: ChannelMessageManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildChannelsManager.js

@@ -22,6 +22,10 @@ class GuildChannelsManager extends BaseCacheManager {
    */
   constructor(client, guild) {
     super(client, { structureType: GuildChannelsManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildEmojisManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import Emoji from "../structures/Emoji.js";
 import BaseCacheManager from "./BaseCacheManager.js";
 
@@ -15,6 +16,10 @@ class GuildEmojisManager extends BaseCacheManager {
    */
   constructor(client, guild) {
     super(client, { structureType: GuildEmojisManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildInviteManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import { PERMISSIONS } from "../constants.js";
 import Invite from "../structures/Invite.js";
 import checkPermission from "../util/discord/checkPermission.js";
@@ -17,6 +18,10 @@ class GuildInviteManager extends BaseCacheManager {
    */
   constructor(client, guild) {
     super(client, { structureType: GuildInviteManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildManager.js

@@ -14,6 +14,10 @@ class GuildManager extends BaseCacheManager {
    */
   constructor(client) {
     super(client, { structureType: GuildManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildMemberManager.js

@@ -16,6 +16,10 @@ class GuildMemberManager extends BaseCacheManager {
    */
   constructor(client, guild) {
     super(client, { structureType: GuildMemberManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildRoleManager.js

@@ -17,6 +17,10 @@ class GuildRoleManager extends BaseCacheManager {
    */
   constructor(client, guild) {
     super(client, { structureType: GuildRoleManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildScheduledEventManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import ScheduledEvent from "../structures/ScheduledEvent.js";
 import BaseCacheManager from "./BaseCacheManager.js";
 
@@ -7,6 +8,10 @@ class GuildScheduledEventManager extends BaseCacheManager {
   static identifier = "events";
   constructor(client, guild) {
     super(client, { structureType: GuildScheduledEventManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/GuildVoiceStatesManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import VoiceState from "../structures/VoiceState.js";
 import BaseCacheManager from "./BaseCacheManager.js";
 
@@ -8,6 +9,9 @@ class GuildVoiceStatesManager extends BaseCacheManager {
   static identifier = "voicestates";
   constructor(client) {
     super(client, { structureType: GuildVoiceStatesManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
   }
   /**
    * Adds a voice state to the cache.

src/managers/MessagePollManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import { TO_JSON_TYPES_ENUM } from "../constants.js";
 
 /**
@@ -11,6 +12,9 @@ class MessagePollManager {
    * @param {Object} existingResponses Existing responses for a poll.
    */
   constructor(client, existingResponses = {}) {
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be an instance of Client.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/MessageReactionManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import { TO_JSON_TYPES_ENUM } from "../constants.js";
 import Reaction from "../structures/Reaction.js";
 
@@ -13,6 +14,9 @@ class MessageReactionManager {
    * @param {Object} existingReactions Existing reactions for a message.
    */
   constructor(client, guild, existingReactions = {}) {
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be an instance of Client.");
+
     /**
      * The client instance.
      * @type {Client}

src/managers/UserManager.js

@@ -1,3 +1,4 @@
+import Client from "../Client.js";
 import User from "../structures/User.js";
 import BaseCacheManager from "./BaseCacheManager.js";
 
@@ -13,6 +14,10 @@ class UserManager extends BaseCacheManager {
    */
   constructor(client) {
     super(client, { structureType: UserManager });
+
+    if (!(client instanceof Client))
+      throw new TypeError("GLUON: Client must be a Client instance.");
+
     /**
      * The client instance.
      * @type {Client}