Limit user reaction to message

Manuel Celli :

I'm building a simple poll bot for Discord in JavaScript, right now I'm trying to implement max number of reactions per user to a message.

For example, suppose we have the following options for a poll question:

The Question?

Option A

Option B

Option C

Option D

Option E

Each "option" is a reaction to the message given from the bot, I want to make sure that a user cannot react to more than 3 of those options.

My train of thought was to make a messageReactionAdd listener and then when the user reacted for the 4th time, remove the last reaction, sending him a message like "You've already voted 3 times, please remove a reaction to vote again".
Still, I'm stuck trying to navigate through the objects to find the total reaction count per user I can find the total reaction count per emoji but that's not what I need.

Could someone give me some insight on this?

EDIT

Code used to send messages:

Embed = new Discord.MessageEmbed()
                .setColor(0x6666ff)
                .setTitle(question)
                .setDescription(optionsList);

                message.channel.send(Embed).then(messageReaction => {

                for (var i = 0; i < options.length; i++){
                    messageReaction.react(emojiAlphabet[i][0]);
                }

                message.delete().catch(console.error);
              });

cherryblossom :

Try this:

const {Collection} = require('discord.js')

// the messages that users can only react 3 times with
const polls = new Set()
// Collection<Message, Collection<User, number>>: stores how many times a user has reacted on a message
const reactionCount = new Collection()

// when you send a poll add the message the bot sent to the set:
polls.add(message)

client.on('messageReactionAdd', (reaction, user) => {
  // edit: so that this does not run when the bot reacts
  if (user.id === client.user.id) return

  const {message} = reaction

  // only do the following if the message is one of the polls
  if (polls.has(message)) {
    // if message hasn't been added to collection add it
    if (!reactionCount.get(message)) reactionCount.set(message, new Collection())
    // reaction counts for this message
    const userCount = reactionCount.get(message)
    // add 1 to the user's reaction count
    userCount.set(user, (userCount.get(user) || 0) + 1)

    if (userCount.get(user) > 3) {
      reaction.users.remove(user)
      // <@!id> mentions the user (using their nickname if they have one)
      message.channel.send(`<@!${user.id}>, you've already voted 3 times, please remove a reaction to vote again.`)
    }
  }
})

client.on('messageReactionRemove', (reaction, user) => {
  // edit: so that this does not run when the bot reacts
  if (user.id === client.user.id) return

  const {message} = reaction
  const userCount = reactionCount.get(message)
  // subtract 1 from user's reaction count
  if (polls.has(message)) userCount.set(user, reactionCount.get(message).get(user) - 1)
})