lsp.jsx

class User {
  constructor(roles) {
    this.roles = roles;
  }
  
  getRoles() {
    return this.roles;
  }
}
class AdminUser extends User {}

const ordinaryUser = new User(['moderator']);
const adminUser = new AdminUser({role: 'moderator'},{role: 'admin'});

function showUserRoles(user) {
  const roles = user.getRoles();
  roles.forEach((role) => console.log(role));
}

showUserRoles(ordinaryUser);
showUserRoles(adminUser);