function validatePIN (pin) {


    let bool = true;

  let counter = 0;

  for (let i = 0; i < pin.length; i++) {

    if (Number(pin[i]) || Number(pin[i]) === 0 && pin[i] !== ' ') {

        counter++;

    }

}



  if (counter !== pin.length) {

    bool = false;

  }





  if ((pin.length === 4 || pin.length === 6) && bool === true) {

      console.log(true);

  } else {

      console.log(false);

  }



  //return true or false
}


validatePIN('123');