Sweetbook is a set of primitives for cataloging your widgets, test your widgets in different screen sizes using screenshot testing and make development process of your widgets easy.
You can run your widget isolated from entire application and develop your widget with hotreload also you can use cli commands for describe environment of your widget.
You can make screenshots of widget state in different environments and compare screenshots with referance just using cli commands.
You can run Sweetbook in special mode with user interface where you can explore widgets library and change state and environment of your widget.