Попробуйте это;
import { AppAvailability } from '@ionic-native/app-availability';
import { Platform } from 'ionic-angular';
constructor(private appAvailability: AppAvailability, private platform: Platform) { }
let app;
if (this.platform.is('ios')) {
app = 'Viber://';
} else if (this.platform.is('android')) {
app = 'com.viber.voip ';
}
this.appAvailability.check(app)
.then(
(yes: boolean) => console.log(app + ' is available'),
(no: boolean) => console.log(app + ' is NOT available')
);