Classes and Access Modifiers

class Account {
  private balance: number;
  readonly owner: string;

  constructor(owner: string, startingBalance = 0) {
    this.owner = owner;
    this.balance = startingBalance;
  }

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

  getBalance(): number {
    return this.balance;
  }
}

const acct = new Account('Ada', 100);
acct.deposit(50);
console.log(acct.owner, acct.getBalance());

// acct.balance ❌ the compiler rejects this before the code ever runs:
// "Property 'balance' is private and only accessible within class 'Account'"