dprint-plugin-nix

dprint WASM plugin for Nix using nixfmt-rs.

Installation

dprint add kachick/nix

Configuration

Empty works as default

{
  "nix": {
  }
}

Customize if necessary

{
  "nix": {
    "lineWidth": 100,
    "indentWidth": 2
  }
}

Tips

To format Nix code block in markdown, use tags option in official plugin.

dprint add markdown

{
  "markdown": {
    "tags": {
      "nix": "nix"
    }
  }
}

Runs on nix fmt, Replace nixfmt-tree with dprint

{
  formatter = forAllSystems (
    system:
    let
      pkgs = nixpkgs.legacyPackages.${system};
    in
    pkgs.writeShellScriptBin "dprint-fmt" ''
      exec "${lib.getExe pkgs.dprint}" fmt "$@"
    ''
  );
}

Limitation

Because this plugin is updated after upstream nixfmt and nixfmt_rs, it will lag behind the latest upstream.
Please do not use it for nixpkgs or NixOS/ contributions, and use it only in personal repositories.

Motivation

• I prefer running formatters through dprint WASM plugins
• nix fmt doesn't have check option
• nixfmt needs treefmt (nixfmt-tree) to target Nix files in directories
• Format Nix codeblock with the markdown plugin

Acknowledgments

• Thanks to nixfmt for the official Nix formatter.
• Thanks to nixfmt-rs for porting nixfmt to Rust, which makes it easy to use as a WASM plugin.