User Guide | Discount Helper Data
Helper functions are used to provide value formatting and calculation functionality, or to return data from the carts database tables.
The functions can act independently of data within the cart session, using database table ids or custom data directly submitted to the function to return values, rather than for example requiring the row id of an item in the cart.
This independence from data within the cart session means the functions can be used on pages across a site that do not display cart data, or even on items that have not been added to the cart.