Tailwind

So a tailwind executable is installed at _build directory of the project.

The entry point to this module is the two mix tasks tailwind and tailwind.install. When you setup phoenix for the first time, you most likely ran mix setup or mix assets.setup, which ran a mix task tailwind.install --if-missing. This is responsible for downloading a binary appropriate for your platform and placing it in the _build directory of the project. Its the tailwind task that runs the executable which monitors your assets/css folder and the tailwing.config.js for changes to recompile.

Notable Highlights

The code to determine the target label for the tailwind executable is noteworthy. I like how pattern matching and guards make the code so succint compared to traditional if-else clauses. Also to note is the recommended way to document private modules. By writing comments before the function and not using @doc.

https://github.com/phoenixframework/tailwind/blob/8e1869c09fdc36a9bc329ccb48d1e414c61e31be/lib/tailwind.ex#L237-L262