refactor(MessageReaction): ReactionUserStore (#2078)

* refactor(MessageReactions): fetchUsers() is now users.fetch()

made a lovely class for it and all
happify linter


stuff


i know how to code i swear


i lied

* bdistin suggestions

* space suggestions, rename store

* fix count

* documentation update

src/stores/ReactionUserStore.js

@@ -0,0 +1,33 @@
+const DataStore = require('./DataStore');
+/**
+ * A data store to store User models who reacted to a MessageReaction.
+ * @extends {DataStore}
+ */
+class ReactionUserStore extends DataStore {
+  constructor(client, iterable, reaction) {
+    super(client, iterable, require('../structures/User'));
+    this.reaction = reaction;
+  }
+
+  /**
+   * Fetches all the users that gave this reaction. Resolves with a collection of users, mapped by their IDs.
+   * @param {Object} [options] Options for fetching the users
+   * @param {number} [options.limit=100] The maximum amount of users to fetch, defaults to 100
+   * @param {Snowflake} [options.before] Limit fetching users to those with an id lower than the supplied id
+   * @param {Snowflake} [options.after] Limit fetching users to those with an id greater than the supplied id
+   * @returns {Promise<ReactionUserStore<Snowflake, User>>}
+   */
+  async fetch({ limit = 100, after, before } = {}) {
+    const message = this.reaction.message;
+    const users = await this.client.api.channels[message.channel.id].messages[message.id]
+      .reactions[this.reaction.emoji.identifier]
+      .get({ query: { limit, before, after } });
+    for (const rawUser of users) {
+      const user = this.client.users.create(rawUser);
+      this.set(user.id, user);
+    }
+    return this;
+  }
+}
+
+module.exports = ReactionUserStore;