how to make change from shopify public app to storefront

[Sanjay-Makwana]

Hi  I am developing an app. the  was app developed is theme/storefront related and i would like the app to be able to make changes to the storefront

[Jannik_Hansen]

You have to specify more specifically before we are able to point you in the right direction. 

What exactly are you trying to accomplish?

[Sanjay-Makwana]

@Jannik_Hansen hi thanks for response


I build shopify public app. app allow multi discount code and free  item base on certain condition, 
i used this lib https://github.com/osiset/laravel-shopify  

now i want add free item on store front based on app product to free product  enable.
one more tings  allowing multiple discount code on cart and checkout page.   
I hope you understand the  my issue 

[Jannik_Hansen]

Hi there, 

I would look at this: https://shopify.dev/api/ajax/reference/cart

The keyword when you search is including "cart.js" then you can find hundreds of threads regarding this. 

[Sanjay-Makwana]

@Jannik_Hansen  Thanks for your answer.

I know cart.js it was work on shopify theme side that I already done that.   
how I  can access cart.js into the public app  app will be change the cart on store fronted side ?