Check out example codes for "how to get whatsapp groups in app flutter programmatically". It will help you in understanding the concepts better.

Code Example 1

var whatsappUrl ="whatsapp://send?phone=$phone";
await canLaunch(whatsappUrl)? launch(whatsappUrl):print("open whatsapp app link or do a snackbar with notification that there is no whatsapp installed");

Learn ReactJs, React Native from akashmittal.com