This is a demo project that includes a sample catridge for EComm. The example catridge shows how to add hooks to SCAPI.
The most simple way to upload this code to your EComm instance is the use the VSCode plugin "Prophet". Take a look at these docs to learn how to use it. The most important step will be to define you dw.json file, which is were you can set the hostname, username, password, and code version. These should be the only details you need to upload your code.
The hook simply modifies the product-search response value so that each search hit has a custom property called c_isInBasket. This property will be true if the product hit is in the current users basket. NOTE: This implementation only works for master/variant type products.