How to call updateFragments when opening a pop-up bucket

Hi!
I am writing my own plugin that allows you to add a price to a shopping cart with an arbitrary price (the price is indicated in the number field)
When adding an item to the cart (and therefore automatically opening the side basket), I would like to trigger an action that will update the side basket (its content). In the developer console, I saw that updateFragments is triggered when adding/deleting and loading a page.

Thanks!