GTM - eCommerce dataLayer

<script>
dataLayer.push({
  'event': 'transaction',
  'ecommerce': {
    'purchase': {
      'actionField': {
        'id': 'T12345',        // Transaction ID. Required
        'affiliation': 'Online Store',
        'revenue': '35.43',   // Total transaction value (incl. tax and shipping)
        'tax':'4.90',
        'shipping': '5.99',
        'coupon': 'SUMMER_SALE'
      },
	  'products': [{          // List of productFieldObjects.
        'name': 'T-Shirt 2',  // Name or ID is required.
        'id': '12345',
        'price': '15.25',
        'brand': 'Metric Labs',
        'category': 'Shirts',
        'variant': 'Gray',
        'quantity': 1,
        'coupon': ''  // Optional fields may be omitted or set to empty string.
       },
       {
        'name': 'T-Shirt 1',
        'id': '67890',
        'price': '33.75',
        'brand': 'Metric Labs',
        'category': 'Shirts',
        'variant': 'Black',
        'quantity': 1
       }] //expand this array if more product exists
    }
  }
});

</script>