How to get the discount code in the script on the payment page?

[sandroid]

Help who can...

To send order data to the Google Tag Manager I add the following script in the settings of the Checkout section:

{% if first_time_accessed %}
  dataLayer.push({
  event: "purchase",
  ecommerce: {
    transaction_id: "{{ order.order_number || order.name }}",
    value: {{ total_price | times: 0.01 }},
    tax: {{ tax_price | times: 0.01 }},
    shipping: {{ shipping_price | times: 0.01 }},
    currency: "{{ order.currency }}",
    discount: "????????????????????????????????????",
    items: [
       {% for line_item in line_items %}{
         item_id: "{{ line_item.product_id }}",
         discount: "??????????????????????",
         item_name: "{{ line_item.variant.title || line_item.title }}",
         currency: "{{ order.currency || shop.currency }}",
         price: "{{ line_item.final_price | times: 0.01 }}",
         quantity: "{{ line_item.quantity }}"
       },

{% endfor %}
]
}
});

Everything works well. Except I don't know how to get coupon information (code). I need to send a discount code in the "discount" field.

Can you please suggest me the object and property. I couldn't find it in the documentation. Tried experimenting with "discount_applications" but couldn't get anything from it (I have no experience with with LiquidJS and how show object in console by it)

[sandroid]

Is this at all even possible? In particular, when the tariff version is not a Plus.

[webhasan]

You can use following code for total discount

discount: {{ checkout.discounts_amount | times: 0.01 }}

For item level discount use following code 

discount': {{ line_item.line_level_total_discount | times: 0.01 }}

[Mitrodol]

Yes, it's possible.
Add this piece of code to your dataLayer push

'coupon': {%- assign disc = "" -%}
                              {%- for disc_temp in checkout.discount_applications -%}
                                    {%- assign disc = disc | append: disc_temp.title -%}
                                    {%- unless forloop.last -%} {%- assign disc = disc | append: ',' -%} {%- endunless -%}
                              {%- endfor -%}
                              '{{ disc }}',

If there will be one discount code applied, it will return one value, e.g. 'Free', if multiple codes applied then 'FreeShip, BlackFriday'

[Mitrodol]

Also, if you are using custom web pixels scripts, you can do this way in your script:

analytics.subscribe("checkout_completed", event => {    
   const discount_titles = checkout.discountApplications.map(discount => discount.title);
  const combinedDiscountTitle = discount_titles.join(', ');
//...
   window.dataLayer.push({
 //...push smth
     'coupon': combinedDiscountTitle