diff --git a/src/client/ClientDataResolver.js b/src/client/ClientDataResolver.js
index bac611258..04ff7aeb6 100644
--- a/src/client/ClientDataResolver.js
+++ b/src/client/ClientDataResolver.js
@@ -10,10 +10,6 @@ const Guild = getStructure('Guild');
 const Channel = getStructure('Channel');
 const GuildMember = getStructure('GuildMember');
 
-function $string(obj) {
-  return (typeof obj === 'string' || obj instanceof String);
-}
-
 /**
  * The DataResolver identifies different objects and tries to resolve a specific piece of information from them, e.g.
  * extracting a User from a Message object.
@@ -31,7 +27,7 @@ class ClientDataResolver {
    * * A Message (resolves to the message author)
    * * A Guild (owner of the guild)
    * * A Guild Member
-   * @typedef {User|String|Message|Guild|GuildMember} UserResolvable
+   * @typedef {User|string|Message|Guild|GuildMember} UserResolvable
    */
 
   /**
@@ -42,7 +38,7 @@ class ClientDataResolver {
   resolveUser(user) {
     if (user instanceof User) {
       return user;
-    } else if ($string(user)) {
+    } else if (typeof user === 'string') {
       return this.client.users.get(user);
     } else if (user instanceof Message) {
       return user.author;
@@ -105,7 +101,7 @@ class ClientDataResolver {
   /**
    * Data that resolves to give a Base64 string, typically for image uploading. This can be:
    * * A Buffer
-   * * A Base64 String
+   * * A Base64 string
    * @typedef {Buffer|string} Base64Resolvable
    */
 
@@ -139,7 +135,7 @@ class ClientDataResolver {
       return channel;
     }
 
-    if ($string(channel)) {
+    if (typeof channel === 'string') {
       return this.client.channels.get(channel.id);
     }
 
@@ -147,20 +143,20 @@ class ClientDataResolver {
   }
 
   /**
-   * Data that can be resolved to give a String. This can be:
-   * * A String
+   * Data that can be resolved to give a string. This can be:
+   * * A string
    * * An Array (joined with a new line delimiter to give a string)
    * * Any object
    * @typedef {string|Array|Object} StringResolvable
    */
 
   /**
-   * Resolves a StringResolvable to a String
+   * Resolves a StringResolvable to a string
    * @param {StringResolvable} StringResolvable the string resolvable to resolve
    * @returns {string}
    */
   resolveString(data) {
-    if (data instanceof String) {
+    if (typeof data === 'string') {
       return data;
     }
 
@@ -185,7 +181,7 @@ class ClientDataResolver {
    * @returns {string|Buffer}
    */
   resolveFile(resource) {
-    if ($string(resource)) {
+    if (typeof resource === 'string') {
       return new Promise((resolve, reject) => {
         if (/^https?:\/\//.test(resource)) {
           request.get(resource)
diff --git a/src/client/rest/RESTMethods.js b/src/client/rest/RESTMethods.js
index cf0cb32a2..68736fc12 100644
--- a/src/client/rest/RESTMethods.js
+++ b/src/client/rest/RESTMethods.js
@@ -464,7 +464,7 @@ class RESTMethods {
       if (_data.permissions) {
         let perms = 0;
         for (let perm of _data.permissions) {
-          if (perm instanceof String || typeof perm === 'string') {
+          if (typeof perm === 'string') {
             perm = Constants.PermissionFlags[perm];
           }
           perms |= perm;
diff --git a/src/structures/DMChannel.js b/src/structures/DMChannel.js
index c71d603f0..8cf633f2a 100644
--- a/src/structures/DMChannel.js
+++ b/src/structures/DMChannel.js
@@ -31,7 +31,7 @@ class DMChannel extends Channel {
   }
 
   /**
-   * When concatenated with a String, this automatically concatenates the recipient's mention instead of the
+   * When concatenated with a string, this automatically concatenates the recipient's mention instead of the
    * DM channel object.
    * @returns {string}
    */
diff --git a/src/structures/Emoji.js b/src/structures/Emoji.js
index 9e8d97c7c..6a9660749 100644
--- a/src/structures/Emoji.js
+++ b/src/structures/Emoji.js
@@ -68,7 +68,7 @@ class Emoji {
   }
 
   /**
-   * When concatenated with a String, this automatically returns the emoji mention rather than the object.
+   * When concatenated with a string, this automatically returns the emoji mention rather than the object.
    * @returns {string}
    * @example
    * // send an emoji:
diff --git a/src/structures/EvaluatedPermissions.js b/src/structures/EvaluatedPermissions.js
index 7a71d4fd0..bcb9ac385 100644
--- a/src/structures/EvaluatedPermissions.js
+++ b/src/structures/EvaluatedPermissions.js
@@ -39,7 +39,7 @@ class EvaluatedPermissions {
    * @returns {boolean}
    */
   hasPermission(permission, explicit = false) {
-    if (permission instanceof String || typeof permission === 'string') {
+    if (typeof permission === 'string') {
       permission = Constants.PermissionFlags[permission];
     }
 
diff --git a/src/structures/Guild.js b/src/structures/Guild.js
index 7dff83dbb..458539ffd 100644
--- a/src/structures/Guild.js
+++ b/src/structures/Guild.js
@@ -151,7 +151,7 @@ class Guild {
   }
 
   /**
-   * When concatenated with a String, this automatically concatenates the Guild's name instead of the Guild object.
+   * When concatenated with a string, this automatically concatenates the Guild's name instead of the Guild object.
    * @returns {string}
    * @example
    * // logs: Hello from My Guild!
diff --git a/src/structures/GuildChannel.js b/src/structures/GuildChannel.js
index d5bb55fd8..c10cade55 100644
--- a/src/structures/GuildChannel.js
+++ b/src/structures/GuildChannel.js
@@ -263,7 +263,7 @@ class GuildChannel extends Channel {
   }
 
   /**
-   * When concatenated with a String, this automatically returns the Channel's mention instead of the Channel object.
+   * When concatenated with a string, this automatically returns the Channel's mention instead of the Channel object.
    * @returns {string}
    * @example
    * // Outputs: Hello from #general
diff --git a/src/structures/Role.js b/src/structures/Role.js
index 472ff1322..f8407e8b2 100644
--- a/src/structures/Role.js
+++ b/src/structures/Role.js
@@ -198,7 +198,7 @@ class Role {
    * }
    */
   hasPermission(permission, explicit = false) {
-    if (permission instanceof String || typeof permission === 'string') {
+    if (typeof permission === 'string') {
       permission = Constants.PermissionFlags[permission];
     }
 
@@ -216,7 +216,7 @@ class Role {
   }
 
   /**
-   * When concatenated with a String, this automatically concatenates the Role mention rather than the Role object.
+   * When concatenated with a string, this automatically concatenates the Role mention rather than the Role object.
    * @returns {string}
    */
   toString() {
diff --git a/src/structures/User.js b/src/structures/User.js
index 769d5350b..34a09cb54 100644
--- a/src/structures/User.js
+++ b/src/structures/User.js
@@ -56,7 +56,7 @@ class User {
   }
 
   /**
-   * When concatenated with a String, this automatically concatenates the User's mention instead of the User object.
+   * When concatenated with a string, this automatically concatenates the User's mention instead of the User object.
    * @returns {string}
    * @example
    * // logs: Hello from <@123456789>!
diff --git a/src/structures/interface/TextBasedChannel.js b/src/structures/interface/TextBasedChannel.js
index 211a8742a..755b0ef76 100644
--- a/src/structures/interface/TextBasedChannel.js
+++ b/src/structures/interface/TextBasedChannel.js
@@ -196,7 +196,7 @@ class TextBasedChannel {
    */
   sendFile(attachment, fileName) {
     if (!fileName) {
-      if (attachment instanceof String || typeof attachment === 'string') {
+      if (typeof attachment === 'string') {
         fileName = path.basename(attachment);
       } else if (attachment && attachment.path) {
         fileName = path.basename(attachment.path);