JavaScript classes and prototype-based inheritance

                  // ES6 Class syntax
class Person {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }

  greet() {
    return `Hello, I'm ${this.name}`;
  }

  get info() {
    return `${this.name}, ${this.age} years old`;
  }

  static species() {
    return 'Homo sapiens';
  }
}

const person = new Person('Alice', 30);
console.log(person.greet());

// Inheritance
class Employee extends Person {
  constructor(name, age, jobTitle) {
    super(name, age);
    this.jobTitle = jobTitle;
  }

  greet() {
    return `${super.greet()}, I work as a ${this.jobTitle}`;
  }
}

// Private fields
class BankAccount {
  #balance = 0;

  deposit(amount) {
    this.#balance += amount;
    return this.#balance;
  }

  get balance() {
    return this.#balance;
  }
}

// Prototype-based
function Animal(name) {
  this.name = name;
}

Animal.prototype.speak = function() {
  return `${this.name} makes a sound`;
};

const dog = new Animal('Dog');
console.log(dog.speak());

// Static methods
class MathUtils {
  static PI = 3.14159;

  static circleArea(radius) {
    return this.PI * radius * radius;
  }
}