Online Store 2.0 - App block data is not re-rendering after variant change

Retired Boards Appdev Store Design
1

Hi,

I have been developing a store 2.0 theme app extension. The app creates app block on product page. The data in the block must change upon selecting a different variant.

For example - app block should display the selected variant-id, but when the variant is changed, the app block does not get refreshed and does not shows the newly selected variant-id. What am i doing wrong ?
Below is the code of the app-block.liquid code -


  

 Variant-id = {{ product.selected_or_first_available_variant.id }}

{% schema %}
{
  "name": "Back in Stock",
  "templates": ["product"],
  "target": "section",
  "stylesheet": "styles.css",
  "javascript": "main.js",
  "settings": []
}
{% endschema %}

I have been stuck with this for couple of days. Any help very appreciated.

Thanks.