Google Tag Manager Script for CartHook

var GTMid = 'GTM-XXXXX'; // Your GTM id here
var orderId = window.chData.order.carthook_order_id;
var lastChargedLineItems = window.chData.order.last_charged_line_items;
window.dataLayer = window.dataLayer || [];
var transactionProducts = [];
var taxPrice = 0;
var subtotalPrice = 0;
for (var i = 0; i < lastChargedLineItems.length; i++) {
  var item = lastChargedLineItems[i];
  transactionProducts.push({
    'sku': item.sku,
    'name': item.title,
    'price': item.price,
    'quantity': item.quantity,
  });
  if (item.tax_amount) {
    taxPrice += item.tax_amount;
  }
  subtotalPrice += (item.price * item.quantity);
}
var shippingRates = window.chData.order.last_charged_shipping_rates;
var shippingTotal = 0; //Sum up shipping
for (var i = 0; i < shippingRates.length; i++) {
  shippingTotal += parseFloat(shippingRates[i].price);
}
if (transactionProducts.length > 0) {
  window.dataLayer.push({
    'event': 'transactionComplete',
    'transactionId': orderId,
    'transactionTotal': parseFloat(subtotalPrice),
    'transactionTax': parseFloat(taxPrice),
    'transactionShipping': parseFloat(shippingTotal),
    'transactionProducts': transactionProducts
  });
}
(function(w, d, s, l, i) {
  w[l] = w[l] || [];
  w[l].push({
    'gtm.start': new Date().getTime(),
    event: 'gtm.js'
  });
  var f = d.getElementsByTagName(s)[0],
    j = d.createElement(s),
    dl = l != 'dataLayer' ? '&l=' + l : '';
  j.async = true;
  j.src = 'https://www.googletagmanager.com/gtm.js?id=' + i + dl;
  f.parentNode.insertBefore(j, f);
})(window, document, 'script', 'dataLayer', GTMid);