client.on('guildMemberUpdate', async (oldMember, newMember) => {
const hadRole = oldMember.roles.find(role => role.name === 'Nitro Booster');
const hasRole = newMember.roles.find(role => role.name === 'Nitro Booster');
if (!hasRole && hadRole) {
// пользователь снял буст
}
});