I am creating a private app for a customer for which I am using Nodejs and express.
The app needs to show a pop-up when user clicks "checkout".
This pop-up will ask for a special code and if the code is valid then it will apply a discount.
I am a first time developer. So far I have managed to register a webhook to checkout.
My server does receive an event when user clicks checkout.
However at this point I am not sure how to proceed i.e how do I show a modal and capture the input from that modal.
Any suggestions would be appreciated.
Webhooks are not meant to be so fast that you can make some change to the storefront before the intended action happens, in this case redirecting the customer to checkout. You will need to directly interact with the storefront either using theme customizations, or using a ScriptTag. Check out some (hopefully) useful docs below.