Cum sa folosesti clase in JavaScript

class User {
    constructor(name, email) {
        this.name = name;
        this.email = email;
        this.createdAt = new Date();
    }

    getInfo() {
        return `${this.name} <${this.email}>`;
    }

    isNew() {
        const daysSinceCreation = (Date.now() - this.createdAt) / 86400000;
        return daysSinceCreation < 7;
    }
}

const user = new User('Ion Popescu', 'ion@example.com');
console.log(user.getInfo());

class Product {
    constructor(price, vatRate = 0.19) {
        this._price = price;
        this._vatRate = vatRate;
    }

    get priceWithVAT() {
        return this._price * (1 + this._vatRate);
    }

    set price(value) {
        if (value < 0) throw new Error('Pretul nu poate fi negativ');
        this._price = value;
    }

    get price() {
        return this._price;
    }
}

const p = new Product(100);
console.log(p.priceWithVAT);
p.price = 200;
console.log(p.priceWithVAT);

class Animal {
    constructor(name) {
        this.name = name;
    }

    speak() {
        return `${this.name} face un sunet.`;
    }
}

class Dog extends Animal {
    constructor(name, breed) {
        super(name);
        this.breed = breed;
    }

    speak() {
        return `${this.name} latra!`;
    }

    getBreed() {
        return this.breed;
    }
}

const dog = new Dog('Rex', 'Ciobanesc');
console.log(dog.speak());
console.log(dog.getBreed());

class MathUtils {
    static add(a, b) {
        return a + b;
    }

    static fromJSON(json) {
        const data = JSON.parse(json);
        return new User(data.name, data.email);
    }
}

console.log(MathUtils.add(5, 3));

class BankAccount {
    #balance = 0;

    constructor(owner) {
        this.owner = owner;
    }

    deposit(amount) {
        if (amount <= 0) throw new Error('Suma invalida');
        this.#balance += amount;
        return this.#balance;
    }

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

const account = new BankAccount('Ion');
account.deposit(500);
console.log(account.getBalance());