He mirado varias guías en línea y en su mayoría usan este comando

 let role = message.guild.roles.cache.find(r => r.id === "Role ID"); // The member you want to add the role to let member = message.mentions.members.first(); // Add role to the member member.roles.add(role); // Or add it to yourself message.author.roles.add(role);

Intenté esto mucho y esta es mi implementación de ese código.

 if (message.member.roles.cache.some(role => role.name === "Co-Owner" || role.name === "Operator")) { if (command == "birthday") { const mention = message.mentions.users.first() || client.users.get(args[0]); var role = message.guild.roles.cache.find(role => role.name === "BIRTHDAY POG"); if (mention.roles.cache.some(role => role.name === "BIRTHDAY POG")) { message.reply("The user has already the role, the role will now be removed"); mention.roles.remove(role); } else { mention.roles.add(role); message.reply("The role has been added to `" + mention.username + "`"); client.guilds.cache.get('731368965963513936').channels.cache.get('778124805135663104').send(message.author.username + " has used the command Birthday to " + mention.username); message.reply("Use the same command with the person to remove the role"); } } }

Este comando debería agregar el rol de cumpleaños al usuario mencionado pero no puedo hacerlo funcionar, da este error

 if (mention.roles.cache.some(role => role.name === "BIRTHDAY POG")) { ^ TypeError: Cannot read property 'cache' of undefined

¿Alguien me puede ayudar?