From looking at the example this plugin seems to be for listening to custom events triggered in native (Cordova plugin) code. Are you sure it works with key events like you are trying to use it?
I don’t actually know - I just had a 2 minute look at the docs of the plugin. Maybe ask in the plugin Github issues if you don’t get a good answer around here.
(You might also want to open a second topic here where you ask how to solve the actual task you have, which seems to be executing some code when someone presses a specific key)