Shopify dataLayer (Checkout - Purchase)

Shopify-dataLayer.js

{% if first_time_accessed %}
<script>                               
window.dataLayer = window.dataLayer || [];                                            
var shipping_price = '{{shipping_price | money_without_currency }}';
shipping_price  = shipping_price.replace(",", ".");
var total_price = '{{total_price | money_without_currency }}';
total_price  = total_price.replace(",", ".");
var tax_price = '{{tax_price | money_without_currency }}';
tax_price  = tax_price.replace(",", ".");
window.dataLayer.push({
  'page_type': 'purchase',
  'event': 'analyzify_purchase',
  'currency': "{{ shop.currency }}",
  'totalValue': total_price,
  'shipping': shipping_price,
  'tax': tax_price,
  'payment_type': '{{order.transactions[0].gateway}}',
  'transaction_id': "{{order.name}}",
});
</script> 
{% endif %}