how to give a role to a new member in 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)

var role = message.guild.roles.find(role => role.name === "MyRole");
message.member.addRole(role);