How to close webview after the work is done in react native

I am using following code to render a webview:

const someHTMLFile = require('./somefile.html')
render() {
  return (
     <View style={{flex: 1}}>
      <WebView
          style={{flex: 1}}
          source={someHTMLFile}
          ref={( webView ) => this.webView = webView}
      />      
    </View>
  );
}

In this html file, there is a form which is automatically submitted when the webview loads (with some data sent from reactnative part of code) and in the end, the file is redirected to a specific url, where some processing is done (on the send data), and right now, it returns nothing. So the screen goes blank.

So, at this point, I want to close the webview and take the user back to my reactnative app.. So, how can I do that? any suggestions?