@deodad
on web just render a button
on iOS its as easy as setting allowsBackForwardNavigationGestures on the WebView component from react-native-webview to true when back state is visible
on android this isn't supported but you can plug into the `hardwareBackPress` event like so
https://gist.github.com/deodad/834ac4b5e33217c4b2fffe292a8f2e22
hmu if you have qs