I am working on a discord bot who is supposed to ban members that reacted to a specific message with a specific emote. The file I created for the messageReactionAdd event currently contains the following code:

module.exports = {
    name: 'messageReactionAdd',
    execute(client, reaction, user) {
        const channel = client.channels.cache.find(channel => channel.name === 'test');
        let message = 874736592542105640;
        let emotes = ['kannathinking', '🍎'];
        let roleID = (reaction.emoji.name == emotes[0] ? '874730080486686730' : '874729987310235738')

        if (message == reaction.message.id && (emotes[0] == reaction.emoji.name || emotes[1] == reaction.emoji.name)) {
        user.ban();
        channel.send(`${user} was banned`);
        }
    }
}

However this code doesn't work and throws me the following error:

user.ban() is not a function

After doing some research I found out that the ba command only works on GuildMember objects. Unfortunately those aren't created when messageReactionAdd is called. Does anyone have an idea how to work around it?