Important:
- This is a handler function. Implement it only as part of the service plugin.
- When developing websites or building apps with Blocks, use Velo service plugins.
This method retrieves additional fees calculated by your app.
Wix calls this method when certain actions are performed on the cart or checkout.
For example, when an item is added to the cart or the amount of an item is updated in the checkout.
Notes:
- Do not call the Estimate Cart Totals, Estimate Current Cart Totals or Get Checkout methods from your implementation code for Calculate Additional Fees. Doing so will result in an error.
- The currency returned in the response object must match the site's currency or those fees will be filtered out and not returned.