event-handler.js

const path = require('path');
const RequireAll = require('require-all');
const Logger = require('../utils/logger');
const { status, statusType } = require('../../config/bot-config.json');

let discordClient;

module.exports = {
   init(client, args = { launchTimestamp: Date.now() }) {
      discordClient = client;
      this.initEssentialEvents(client, args);
      this.initEvents(client);
   },

   initEssentialEvents(client = discordClient, args = { launchTimestamp: Date.now() }) {
      // Ready event, which gets fired only once when the bot reaches the ready state
      client.once('ready', async () => {
         const updateBotStatus = async () => {
            await client.user.setActivity(status, { type: statusType });
         };

         await updateBotStatus();
         // Updates the bot status every hour
         client.setInterval(() => updateBotStatus(), 3600000);

         Logger.info(`Successfully launched in ${(Date.now() - args.launchTimestamp) / 1000} seconds!`);
      });

      /* Raw listener for messageReactionAdd event
         Uncomment the following code if you need your bot
         to listen to messageReactionAdd events on uncached messages
       */
      /*
      client.on('raw', async (event) => {
         // Listen only to reactionAdd events
         if (event.t !== 'MESSAGE_REACTION_ADD') {
            return;
         }

         const { d: data } = event;
         if (typeof client.channels.cache.get(data.channel_id) === 'undefined') {
            return;
         }

         const channel = await client.channels.fetch(data.channel_id);

         // if the message is already in the cache, don't re-emit the event
         if (channel.messages.cache.has(data.message_id)) {
            return;
         }

         const user = await client.users.fetch(data.user_id);
         const message = await channel.messages.fetch(data.message_id);
         // Custom emoji are keyed by IDs, while unicode emoji are keyed by names
         const reaction = message.reactions.resolve(data.emoji.id || data.emoji.name);

         client.emit('messageReactionAdd', reaction, user);
      });
       */

      // Some other somewhat important events that the bot should listen to
      client.on('error', (err) => Logger.error('The client threw an error', err));

      client.on('shardError', (err) => Logger.error('A shard threw an error', err));

      client.on('warn', (warn) => Logger.warn('The client received a warning', warn));
   },

   initEvents(client = discordClient) {
      // Gets all the events from the events folder
      const events = Object.entries(
         RequireAll({
            dirname: path.join(__dirname, 'events'),
            filter: /^(?!-)(.+)\.js$/,
         }),
      );

      /*
       Binds the events gotten with the code above to the client:
         e[0] is the event name (the name of the file)
         e[1] is the function that will get executed when the event gets fired
       */
      events.forEach((e) => client.on(e[0], e[1].bind(null, client)));
   },
};