I'm trying to make a vanity bot for Discord, but I'm not sure if I'm using the correct event. Here is my code:

client.on("presenceUpdate", newPresence => {
    let vanityRole = newPresence.guild.roles.cache.find(role => role.id === "940679835456536596");
  const activity = newPresence.member.user.presence.activities[0].state
  if (activity === null) return;
  if (activity.includes("gg/pm")) {
    let memberTarget = newPresence.guild.members.cache.get(newPresence.member.id);
    memberTarget.roles.add(vanityRole);
    const vanity = new Discord.MessageEmbed()
      .setColor(color)
      .setDescription(`<@${memberTarget.id}>, thanks for putting us in your status <3`);
      message.channel.send(vanity)
  }
  else return;
});

Here is the error I'm receiving: On this line: const activity = newPresence.member.user.presence.activities[0].state Error: [TypeError: Cannot read property 'state' of undefined] repl process died unexpectedly: exit status 1

Thanks