neovim-flake/docs/manual/configuring/custom-plugins/configuring.md

Configuring

Just making the plugin to your Neovim configuration available might not always be enough. In that case, you can write custom lua config using either config.vim.extraPlugins (which has the setup field) or config.vim.luaConfigRC. The first option uses an attribute set, which maps DAG section names to a custom type, which has the fields package, after, setup. They allow you to set the package of the plugin, the sections its setup code should be after (note that the extraPlugins option has its own DAG scope), and the its setup code respectively. For example:

config.vim.extraPlugins = with pkgs.vimPlugins; {
  aerial = {
    package = aerial-nvim;
    setup = "require('aerial').setup {}";
  };

  harpoon = {
    package = harpoon;
    setup = "require('harpoon').setup {}";
    after = ["aerial"]; # place harpoon configuration after aerial
  };
}

The second option also uses an attribute set, but this one is resolved as a DAG directly. The attribute names denote the section names, and the values lua code. For example:

{
  # this will create an "aquarium" section in your init.lua with the contents of your custom config
  # which will be *appended* to the rest of your configuration, inside your init.vim
  config.vim.luaConfigRC.aquarium = "vim.cmd('colorscheme aquiarum')";
}

:::{.note} If your configuration needs to be put in a specific place in the config, you can use functions from inputs.nvf.lib.nvim.dag to order it. Refer to https://github.com/nix-community/home-manager/blob/master/modules/lib/dag.nix to find out more about the DAG system. :::

If you successfully made your plugin work, please feel free to create a PR to add it to nvf or open an issue with your findings so that we can make it available for everyone easily.