import {Push, PushObject, PushOptions} from '@ionic-native/push/ngx';
...
if (this.platform.is('cordova')) {

                const options: PushOptions = {
                    android: {},
                    ios: {
                        alert: 'true',
                        badge: true,
                        sound: 'true'
                    }
                }

                const pushObject: PushObject = this.push.init(options);

                pushObject.on('registration').subscribe((registration: any) => {

// "registration.registrationId" now holds the token that needs to be sent back to jBackend

});
});