Querying By Categories
besides that you can query your products for the whole store, you can also query with specific category in your store using category(), like this:
Using await/async :
List<Product> allProducts = await YouCan.instance.categories.category('YOUR CATEGORY ID').products.all();
Using A FutureBuilder :
FutureBuilder<List<Product>>(
    future: YouCan.instance.categories.category('YOUR CATEGORY ID').products.all(),
    builder: (context, snapshot) {
      if (snapshot.hasData) {
        return Text(snapshot.data);
      } else if (snapshot.hasError) {
        return Text("Error: ${snapshot.error}");
      } else {
        return CircularProgressIndicator();
      }
    },
  ),