GuildEmoji: Move all role related functions to a separate store (#2271)

* Prepare to work on moving all role functions to a Store

And yes, this is *another* patch branch cause I messed up my master branch to hell

* Move all emoji role related functions to its own store
Tested everything and it works! (With a reload of the client)
Also had to change a value in DataStore#holds
holds.name for GuildEmojis would return the emoji name instead of the class name

* New Line

* Thanks JS for circular dependency!
Because we can't have nice things...

* Do space's request

* Fix equals

* Fix space's point.

Raw API data has the role property as an array of IDs

src/stores/GuildEmojiRoleStore.js

@@ -0,0 +1,110 @@
+const DataStore = require('./DataStore');
+const Collection = require('../util/Collection');
+const { TypeError } = require('../errors');
+
+/**
+ * Stores emoji roles
+ * @extends {DataStore}
+ */
+class GuildEmojiRoleStore extends DataStore {
+  constructor(emoji) {
+    super(emoji.client, null, require('../structures/GuildEmoji'));
+    this.emoji = emoji;
+    this.guild = emoji.guild;
+  }
+
+  /**
+   * Adds a role (or multiple roles) to the list of roles that can use this emoji.
+   * @param {RoleResolvable|RoleResolvable[]|Collection<Snowflake, Role>} roleOrRoles The role or roles to add
+   * @returns {Promise<GuildEmoji>}
+   */
+  add(roleOrRoles) {
+    if (roleOrRoles instanceof Collection) return this.add(roleOrRoles.keyArray());
+    if (!(roleOrRoles instanceof Array)) return this.add([roleOrRoles]);
+
+    roleOrRoles = roleOrRoles.map(r => this.guild.roles.resolve(r));
+
+    if (roleOrRoles.includes(null)) {
+      return Promise.reject(new TypeError('INVALID_TYPE', 'roles',
+        'Array or Collection of Roles or Snowflakes', true));
+    } else {
+      for (const role of roleOrRoles) super.set(role.id, role);
+    }
+
+    return this.set(this);
+  }
+
+  /**
+   * Removes a role (or multiple roles) from the list of roles that can use this emoji.
+   * @param {RoleResolvable|RoleResolvable[]|Collection<Snowflake, Role>} roleOrRoles The role or roles to remove
+   * @returns {Promise<GuildEmoji>}
+   */
+  remove(roleOrRoles) {
+    if (roleOrRoles instanceof Collection) return this.remove(roleOrRoles.keyArray());
+    if (!(roleOrRoles instanceof Array)) return this.remove([roleOrRoles]);
+
+    roleOrRoles = roleOrRoles.map(r => this.guild.roles.resolveID(r));
+
+    if (roleOrRoles.includes(null)) {
+      return Promise.reject(new TypeError('INVALID_TYPE', 'roles',
+        'Array or Collection of Roles or Snowflakes', true));
+    } else {
+      for (const role of roleOrRoles) super.remove(role);
+    }
+
+    return this.set(this);
+  }
+
+  /**
+   * Sets the role(s) that can use this emoji.
+   * @param {Collection<Snowflake, Role>|RoleResolvable[]} roles The roles or role IDs to apply
+   * @returns {Promise<GuildEmoji>}
+   * @example
+   * // Set the emoji's roles to a single role
+   * guildEmoji.roles.set(['391156570408615936'])
+   *   .then(console.log)
+   *   .catch(console.error);
+   * @example
+   * // Remove all roles from an emoji
+   * guildEmoji.roles.set([])
+   *    .then(console.log)
+   *    .catch(console.error);
+   */
+  set(roles) {
+    return this.emoji.edit({ roles });
+  }
+
+  /**
+   * Patches the roles for this store
+   * @param {Snowflake[]} roles The new roles
+   * @private
+   */
+  _patch(roles) {
+    this.clear();
+
+    for (let role of roles) {
+      role = this.guild.roles.resolve(role);
+      if (role) super.set(role.id, role);
+    }
+  }
+
+  /**
+   * Resolves a RoleResolvable to a Role object.
+   * @method resolve
+   * @memberof GuildEmojiRoleStore
+   * @instance
+   * @param {RoleResolvable} role The role resolvable to resolve
+   * @returns {?Role}
+   */
+
+  /**
+   * Resolves a RoleResolvable to a role ID string.
+   * @method resolveID
+   * @memberof GuildEmojiRoleStore
+   * @instance
+   * @param {RoleResolvable} role The role resolvable to resolve
+   * @returns {?Snowflake}
+   */
+}
+
+module.exports = GuildEmojiRoleStore;