Tbh, Im very early in my nativescript experiences (though I do believe in the project). But I believe these are some examples you are looking for

http://docs.nativescript.org/ui/placeholder

http://docs.nativescript.org/core-concepts/accessing-native-...

http://docs.nativescript.org/runtimes/ios/marshalling/Marsha...

http://docs.nativescript.org/runtimes/android/marshalling/ov...

http://docs.nativescript.org/plugins/plugins