How to use the card-validator.expirationDate function in card-validator

                test: value => expirationDate(value).isValid,
            });

export const isExpirationDate = (month, year) => valid.expirationDate({ month, year }).isValid;

validateValues = (formValues) => {
    const numberValidation = valid.number(formValues.number);
    const expiryValidation = valid.expirationDate(formValues.expiry);
    const maxCVCLength = (numberValidation.card || FALLBACK_CARD).code.size;
    const cvcValidation = valid.cvv(formValues.cvc, maxCVCLength);

    const validationStatuses = pick({
      number: toStatus(numberValidation),
      expiry: toStatus(expiryValidation),
      cvc: toStatus(cvcValidation),
      name: !!formValues.name ? "valid" : "incomplete",
      postalCode: this._validatePostalCode(formValues.postalCode),
    }, this._displayedFields);

    return {
      valid: every(values(validationStatuses), status => status === "valid"),
      status: validationStatuses,
    };
  };

function confirmAddCardClicked(event) {
  var name = document.getElementById("full-name").value;
  var expDate = document.getElementById("exp-date").value;
  var expMonth = expDate.substring(5);
  var expYear = expDate.substring(0, 4);
  var number = document.getElementById("cc-number").value;

  var validationResult = cardValidator.number(number);
  var expDateValidation = cardValidator.expirationDate({ month: expMonth , year: expYear });

  addCardConfirmed(name, number, expMonth, expYear);
  $("#add-card-modal").modal("toggle");
}

function cardInfoUpdated(event) {
  var name = document.getElementById("full-name").value;
  var expDate = document.getElementById("exp-date").value;
  var number = document.getElementById("cc-number").value;

  var validationResult = cardValidator.number(number);
  var expDateValidation = cardValidator.expirationDate({ month: expDate.substring(5) , year: expDate.substring(0, 4) });

  var readyToSave = validationResult.isValid && expDateValidation.isValid && name.length > 0;
  document.getElementById("add-card-confirm-button").disabled = !readyToSave;

  var formattedNumber = formatCardNumber(number);
  if (number !== formattedNumber) {
    document.getElementById("cc-number").value = formattedNumber;
  }
}

CreditCardForm.prototype._onSplitDateChange = function () {
  var validationResult;

  var month = this.get('expirationMonth.value');
  var year = this.get('expirationYear.value');

  var monthValidation = validator.expirationMonth(month);
  var yearValidation = validator.expirationYear(year);

  if (monthValidation.isValid && yearValidation.isValid) {
    validationResult = validator.expirationDate(month + year);

    this.set('expirationMonth.isValid', validationResult.isValid);
    this.set('expirationMonth.isPotentiallyValid', validationResult.isPotentiallyValid);
    this.set('expirationYear.isValid', validationResult.isValid);
    this.set('expirationYear.isPotentiallyValid', validationResult.isPotentiallyValid);
  } else {
    this.set('expirationMonth.isValid', monthValidation.isValid);
    this.set('expirationMonth.isPotentiallyValid', monthValidation.isPotentiallyValid);
    this.set('expirationYear.isValid', yearValidation.isValid);
    this.set('expirationYear.isPotentiallyValid', yearValidation.isPotentiallyValid);
  }
};