var elArr = [description, amount];

if (invoiceidDiv.firstChild.innerHTML.length > 1) {
  invoiceidDiv.style.display = "block";
}

var purchase_units = [];
purchase_units[0] = {};
purchase_units[0].amount = {};

function validate(event) {
  return event.value.length > 0;
}

paypal.Buttons({
  style: {
    color: 'gold',
    shape: 'pill',
    label: 'paypal',
    layout: 'horizontal',

  },

  onInit: function (data, actions) {
    actions.disable();

    if(invoiceidDiv.style.display === "block") {
      elArr.push(invoiceid);
    }

    elArr.forEach(function (item) {
      item.addEventListener('keyup', function (event) {
        var result = elArr.every(validate);
        if (result) {
          actions.enable();
        } else {
          actions.disable();
        }
      });
    });
  },

  onClick: function () {
    if (description.value.length < 1) {
      descriptionError.style.visibility = "visible";
    } else {
      descriptionError.style.visibility = "hidden";
    }

    if (amount.value.length < 1) {
      priceError.style.visibility = "visible";
    } else {
      priceError.style.visibility = "hidden";
    }

    if (invoiceid.value.length < 1 && invoiceidDiv.style.display === "block") {
      invoiceidError.style.visibility = "visible";
    } else {
      invoiceidError.style.visibility = "hidden";
    }

    purchase_units[0].description = description.value;
    purchase_units[0].amount.value = amount.value;

    if(invoiceid.value !== '') {
      purchase_units[0].invoice_id = invoiceid.value;
    }
  },

  createOrder: function (data, actions) {
    return actions.order.create({
      purchase_units: purchase_units,
    });
  },

  onApprove: function (data, actions) {
    return actions.order.capture().then(function (orderData) {

      // Full available details
      console.log('Capture result', orderData, JSON.stringify(orderData, null, 2));

      // Show a success message within this page, e.g.
      const element = document.getElementById('paypal-button-container');
      element.innerHTML = '';
      element.innerHTML = '<h3>Thank you for your payment!</h3>';

      // Or go to another URL:  actions.redirect('thank_you.html');

    });
  },

  onError: function (err) {
    console.log(err);
  }
}).render('#paypal-button-container');