Ionic 4 + WhatsApp share - Get receiver / contact details after I share my message

I am using Ionic 4 + SocialSharing-PhoneGap-Plugin.

1. After I share a message with my contact, how can I get back the contact's name/number and other info back in the promise, so that I can save it in the database?

I have the following code:

import { SocialSharing } from '@ionic-native/social-sharing/ngx';

constructor(private socialSharing: SocialSharing) { }

// Share message via WhatsApp
this.socialSharing.shareViaWhatsApp('Hi', null, null).then(() => {
  // How to get the contact's details here, with whom
 // I shared my message? Would like to get the name, number 
 // and all other contact info.

// Following Toast does not seem to trigger
this.toastService.presentToast('Successfully shared coupon on WhatsApp', 'success');
}).catch(() => {
  // Sharing via WhatsApp is not possible. How to trigger a toast here as well?
});

2. How can I show a toast message immediately after return, so that I know that the message was shared successfully? As can be seen from the code, I have a toastService that shows the toast, but it never gets triggered. How can I trigger the toast after successfully sharing my message on WhatsApp, both in success & error cases?

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