discord.js (role).id code example

Example 1: get discord.js role

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);

Example 2: if member has role discord.js

let allowedRole = message.guild.roles.find("name", "rolename");
    if (message.member.roles.has(allowedRole.id) {
        // allowed access to command
    } else {
       // not allowed access
    })