Why is my code not working? I try when someone says: spam the bot begins spamming (it does but it will not stop) How can I fix this problem?

client.on("message", msg => {
  

let interval;

if (msg.content === 'yoyo') { 
  // ...
  if (!interval) {
    interval = setInterval(function() {
      msg.channel.send('yo')
        .catch(console.error);
    }, 1 * 5000);
  } else {
    message.channel.send('yo already running');
  }
}

if (msg.content === 'stop') {
  clearInterval(interval);
  interval = 1 * 1000000;
}
});