Marking a resource with resources.PostProcess delays any transformations to after the build, typically because one or more of the steps in the transformation chain depends on the result of the build (e.g. files in public).
The below configuration will write a hugo_stats.json file to the project root as part of the build. If you’re only using this for the production build, you should consider placing it below config/production.
Note that in the example above, the “CSS purge step” will only be applied to the production build. This means that you need to do something like this in your head template to build and include your CSS:
These are the environment variables Hugo passes down to PostCSS (and Babel), which allows you do do process.env.HUGO_ENVIRONMENT === 'production' ? [autoprefixer] :  and similar:
The absolute path to the project working directory.
The value e.g. set with hugo -e production (defaults to production for hugo and development for hugo server).
The absolute path to the publish directory (the public directory). Note that the value will always point to a directory on disk even when running hugo server in memory mode. If you write to this folder from PostCSS when running the server, you could run the server with one of these flags:
hugo server --renderToDisk
hugo server --renderStaticToDisk
Also, Hugo will add environment variables for all files mounted below assets/_jsconfig. A default mount will be set up with files in the project root matching this regexp: (babel|postcss|tailwind)\.config\.js.
These will get environment variables named on the form HUGO_FILE_:filename: where :filename: is all upper case with periods replaced with underscore. This allows you to do this and similar: