discord.js guild member on role added code example
Example: how to give roles discord.js
let role = message.guild.roles.find(r => r.name === "Role Name");
// Let's pretend you mentioned the user you want to add a role to (!addrole @user Role Name):
let member = message.mentions.members.first();
// or the person who made started the command: let member = message.member;
//adds the role
member.roles.add(role)