Gatsby example site that shows use of mobx.
To use mobx in a Gatsby site you'll need to hook in to two of Gatsby's extension points.
Once in wrapRootElement which runs during Gatsby's server rendering process, and once in wrapRootElement which is part of Gatsby's browser APIs.
Check out ./gatsby-ssr.js and ./gatsby-browser.js to see how this is implemented in this example.
mobx-react-devtools package is now deprecated and was removed. As it could generate the error Cannot read property 'on' of undefined.
To allow access to some form of development tools, install the plugin for your browser of choice like mentioned here.