How to use the map-keydown prop with composition api?

[herleenf]

I want to customize keydown behaviors so that the following are achieved:

1. The vm.search value will change accordingly to which option is highlighted
2. Pressing the enter key will change the value of the model itself.

I have been reading the documentation but the code is written in Options API. I'm considering the possibility that this is an issue in single select. I can work the behaviors just fine but I don't know how to access the return values in the example.