JSFiddle - React, Tailwind, and code Playground

HTML

<!--  Open the console to see the output. -->

JavaScript

class Person{
 constructor(firstName, lastName, age) {
   this.firstName = firstName;
   this.lastName = lastName;
   this.age = age;
 }
 displayName() {
  return `${this.firstName} - ${this.lastName}`;
 }
}
class Employee extends Person {
 constructor(firstName, lastName, age, salary) {
  super(firstName, lastName, age);
  this.salary = salary;
 }
 displaySalary() {
  return `${this.salary}`;
 }
 displayName() {
  return super.displayName();
 }
 displayAge() {
  return this.age;
 }
}
let manager = new Employee("Jon", "Snow", 23, 100);
console.log(manager.displaySalary());
console.log(manager.displayName());
console.log(manager.displayAge());