Getters, Setters, and Private Fields

Classes can expose computed properties and guard internal state using get/set, and truly hide data using private fields.

class BankAccount {
  #balance = 0; // private field (ES2022)

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

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

  deposit(amount) {
    if (amount > 0) this.#balance += amount;
  }

  static bankName = "Sonali Digital"; // static property
}

const acc = new BankAccount("Rima");
acc.deposit(500);
console.log(acc.balance); // 500 (read through the getter)
// console.log(acc.#balance); // ❌ SyntaxError — truly inaccessible from outside

Fields prefixed with #, standardized in ES2022, are enforced as private by the language itself — they can't be read, written, or even detected from outside the class, unlike the old convention of naming a property _balance and hoping nobody touches it directly.

get/set accessors look like plain properties from the outside (acc.balance, no parentheses) but run custom logic underneath, letting you validate on write or compute a value on read while keeping the real data private. static members belong to the class itself rather than to instances, useful for constants or utility methods shared across every instance.