script.liquid

{% if event.preview %}
  {% capture inventory_level_json %}
    {
      "inventory_item_id": 271878346596884015,
      "location_id": 48752903,
      "available": 5
    }
  {% endcapture %}

  {% assign inventory_level = inventory_level_json | parse_json %}
{% endif %}

{% assign cache_key = "inventory_level:" | append: inventory_level.inventory_item_id | append: "/" | append: inventory_level.location_id %}

{% assign previous_available = cache[cache_key] %}

{% if previous_available != nil %}
  {% assign available_difference = inventory_level.available | minus: previous_available %}
  {% if available_difference >= 0 %}
    {% assign available_difference = "+" | append: available_difference %}
  {% endif %}

  {% action "email" %}
    {
      "to": {{ options.email_recipient__email_required | json }},
      "subject": {{ options.email_subject__required | replace: "AVAILABLE", inventory_level.available | replace: "DIFFERENCE", available_difference | strip | json }},
      "body": {{ options.email_body__required_multiline | replace: "AVAILABLE", inventory_level.available | replace: "DIFFERENCE", available_difference | strip | newline_to_br | json }},
      "reply_to": {{ shop.customer_email | json }},
      "from_display_name": {{ shop.name | json }}
    }
  {% endaction %}
{% endif %}

{% action "cache" %}
  {
    "set": {
      "key": {{ cache_key | json }},
      "value": {{ inventory_level.available }}
    }
  }
{% endaction %}