Usage of ‘after/ftplugin’ directory for filetype-specific configuration

Originally posted on Reddit

Do you create any configuration that is specific to a certain file type (like setting local options or buffer-local variables, creating local mappings, running some function, etc.)?

• No. Sooner or later you probably will. So let’s pretend that the answer is…
• Yes. Do you use autocommands with FileType event for this?
  • No. Good. There is probably nothing valuable for you to read here. Sorry for taking your time.
  • Yes. Although totally doable, there is another approach which is not popularized much. You can create ‘after/ftplugin’ directory within your configuration and put filetype-named files to be sourced for this file type. As a bonus, this is technically a way to create a “filetype plugin”, so you can now say that you are a plugin author and maintainer. Example: ‘after/ftplugin/lua.lua’ will be sourced for ‘lua’ file types (specifically, every time filetype buffer option is set to ‘lua’). Don’t forget to use local variants of setting options (:setlocal or vim.opt_local) and creating mappings (vim.api.nvim_buf_set_keymap()).

This is meant as a Friday post to make more people aware of ‘after/ftplugin’ directory, because I find this approach really more structured than using autocommands. For reference, here is how I do it.

Some further reading:

• :h ftplugin (more in-depth about this approach; not really needed for simple use cases)
• :h ftplugin-special (notes about special things to use in these files)
• :h lua-vim-setlocal (use vim.opt_local to set option locally)
• :h after-directory (use ‘after’ directory so that these options are not overridden by defaults)