Get rectangle co-ordinates

[SL-A-SH]

In the IOS only document scanner package rectangle co-ordinates are returned like so:

onPictureTaken={data => this.setState({
image: data.croppedImage,
initialImage: data.initialImage,
rectangleCoordinates: data.rectangleCoordinates,
})}

But here only the path is returned.
How do I get the rectangle co-ordinates like in the package https://github.com/Michaelvilleneuve/react-native-document-scanner?