discord.js/src/stores/ReactionStore.js

const DataStore = require('./DataStore');
const MessageReaction = require('../structures/MessageReaction');

/**
 * Stores reactions.
 * @private
 * @extends {DataStore}
 */
class ReactionStore extends DataStore {
  constructor(message, iterable) {
    super(message.client, iterable, MessageReaction);
    this.message = message;
  }

  create(data, cache) {
    return super.create(data, cache, { id: data.emoji.id || data.emoji.name, extras: [this.message] });
  }

  /**
   * Data that can be resolved to a MessageReaction object. This can be:
   * * A MessageReaction
   * * A Snowflake
   * @typedef {MessageReaction|Snowflake} MessageReactionResolvable
   */

  /**
    * Resolves a MessageReactionResolvable to a MessageReaction object.
    * @method resolve
    * @memberof ReactionStore
    * @instance
    * @param {MessageReactionResolvable} reaction The MessageReaction to resolve
    * @returns {?MessageReaction}
    */

  /**
    * Resolves a MessageReactionResolvable to a MessageReaction ID string.
    * @method resolveID
    * @memberof ReactionStore
    * @instance
    * @param {MessageReactionResolvable} role The role resolvable to resolve
    * @returns {?string}
    */
}

module.exports = ReactionStore;