class User {
    constructor(firstName, lastName) {
                 this.firstName = firstName;
        this.lastName = lastName;
    }
    
    updateProps(firstName, lastName) {
        this.firstName = firstName;
    this.lastName = lastName;
    }
}
let user = new User("Alex", "BLack");
console.log(user.lastName); // BLack
user.updateProps("Alex", "White")
console.log(user.lastName); // White

class User {
  constructor (props) {
    this.updateProps(props)
  }

  updateProps (props) {
    Object.assign(this, props)
  }
}

const user = new User({ firstName: 'Alex', lastName: 'BLack' })
user.updateProps({ lastName: 'White', job: 'Janitor' })