text: class Customer {
    // TODO: auto public property field
    firstName;
    lastName;
    balance = 0;
  
    constructor(firstName, lastName) {
      // get the property from top
      this.firstName = firstName;
      this.lastName = lastName;
    }
  
    sayHello() {}
  }
  
  const eko = new Customer();
  console.info(eko); // Customer { firstName: undefined, lastName: undefined, balance: 0 }
  