How do you debug cordova runtime errors on device?



I’d like to know how to debug runtime errors… Let’s consider a specific case I have right now :

Right now, I have an error in which I only know the word cordova_not_available… is present… The only plugin ionic cordova plugin -ls installed is cordova-plugin-firebase 1.0.3. So I expect this error on the browser (though I uses if (!'cordova))) ) ; but the problem is that the error also shows in the device when I run the app in ionic devApp

So what is going on ?

I have pasted an image of the error below… I’m from a Java background… How do you guys read the log to debug apps ?