Have you tried to list this in the Gatsby's Plugin page?

[sawirricardo]

I think this will be useful, especially there are many people experiencing with issues like "window undefined" while building with Gatsby.

What do you think of putting this to Gatsby's Plugin page? I put the link here in case you choose to list yours here... https://www.gatsbyjs.org/docs/creating-plugins/

Thank you for your work!