Theme Components and blocks

I’m building a Theme Component to speed up my development of new Hugo sites. As with any development, I repeated myself alot and I’m making this to scratch my own itch. I’ll publish the code under AGPLv3 as soon as I have polished it a bit and documented the main features and patterns.

I’m wondering if it is possible to define blocks in a site-wide way on the theme I’m building on top of my base theme.

Let me explain a bit further. Blocks are awesome if I want to add or replace code in a single, list or section page – but what if I want to make site-wide changes? If I add a _layout/baseof.html to my custom theme on top of the base theme in an attempt to define a block, it will replace the whole baseof.html from the base theme.

Does anyone know of a way to define a block in a theme component so that it affects all pages of a site?