Additional notes for upcoming viewers This seems to be a common problem on macOS: https://github.com/ios-control/ios-sim/issues/253
Temporary solution below this question.
I've worked on a fresh ionic project a few days ago and I had no problems back then whatsoever.
Today I tried to start the development server: ionic cordova run -l but then I got this error message:
No target specified for emulator. Deploying to undefined simulator
Device type "com.apple.CoreSimulator.SimDeviceType.undefined" could not be found.
An error occurred while running subprocess cordova.
Logging currently available devices(ionic cordova run --list) gives me this output:
Available ios devices:
Available ios virtual devices:
It is empty. None devices are available. Not for ios and neither for android.
Ionic version: 4.12.0
Cordova version: 9.0.0
Nodejs version: 11.5.0
I would appreciate any help to make this work again.
Seems like you have upgraded the Mac OS, faced similar problem in past and updating and re-installing iOS-sim was not of much help.
For me following command worked without installing anything further
ionic cordova emulate ios --livereload --consolelogs --target="iPhone-6,com.apple.CoreSimulator.SimRuntime.iOS-12-2"
Also, you can try this one if above don't work
ionic cordova emulate ios --livereload --consolelogs --target="iPhone-6,com.apple.CoreSimulator.SimRuntime.iOS-12-2" --buildFlag="-UseModernBuildSystem=0"