msg.react('👍').then(() => msg.react('👎'));

const filter = (reaction, user) => {
    return ['👍', '👎'].includes(reaction.emoji.name) && user.id === interaction.user.id;
};

msg.awaitReactions({ filter, max: 1, time: 40000, errors: ['time'] })
    .then(collected => {
        const reaction = collected.first();

        if (reaction.emoji.name === '👍') {
            msg.reply('You reacted with a thumbs up.');
        } else {
            msg.reply('You reacted with a thumbs down.');
        }
    })
    .catch(collected => {
        msg.reply('You reacted with neither a thumbs up, nor a thumbs down.');
    });