Two great tools I like to use are React.js and Sketch.app now just got better together with AirBnB’s new open source library React-Sketchapp. It can render your React components to a Sketch design file.
Traditionally your application is designed in a UI design tool like Sketch. From the mockups the developers/designers create the React components based on these designs. Over time these move away from the original Sketch file with revisions over the life of the project/product. The design files need to be updated manually and this can be very time consuming.
But now you can use React-Sketchapp to generate the design files from the actual React components that are used in your application.
When you need to create a new design or modification of a component your Sketch files will be up to date with the latest version of your existing components.
Another cool side effect is you can use data in your designs.