Integrating TalkJS, need device token on iOS and registration token on Android. Where do I find these?

https://talkjs.com/docs/Features/Notifications/Mobile_Push_Notifications/

I'm trying to integrate TalkJS in my Median hybrid app, but it needs a device token on iOS and registration token on Android. I think median_device_info has the device token in apnsToken from median_device_info, but I can't see anywhere where the FCM registration token can be found? Am I missing something or will I need to customise the code to include this in median_device_info?