You can reset a bot by using the client.destroy() method, then calling .login after again. Try something like this:

// set message listener 

client.on('message', message => {

    switch(message.content.toUpperCase()) {

        case '?RESET':

            resetBot(message.channel);

            break;



        // ... other commands

    }

});



// Turn bot off (destroy), then turn it back on

function resetBot(channel) {

    // send channel a message that you're resetting bot [optional]

    channel.send('Resetting...')

    .then(msg => client.destroy())

    .then(() => client.login(<your bot token here>));

}

If you set a ready listener in your bot, you will see that the ready event fires twice. I set up a ready listener like this:

client.on('ready', () => {

    console.log('I am ready!');

});