dmx for VS Code

Dart code generation that runs when you save. Annotate a class and copyWith, equality, hashCode, toString and typed JSON appear inside the same file, below a divider — no part files, no .g.dart, no mixins, no delegating factories, and no build_runner run.

Install

Install dmx — Dart code generation from the VS Code Marketplace, or run:

code --install-extension nimblesite.dmx

For an offline installation, download the VSIX for your platform from the latest GitHub release, then choose Extensions: Install from VSIX... or run code --install-extension path/to/dmx-<target>.vsix.

The extension includes dmx on macOS and Linux x64/ARM64, Alpine x64/ARM64, and Windows x64. On any other platform, install the CLI with Homebrew or Scoop so the universal extension can find it on PATH:

# macOS or Linux
brew install nimblesite/tap/dmx

# Windows
scoop bucket add nimblesite https://github.com/Nimblesite/scoop-bucket
scoop install dmx

Then add the package the generated code uses:

dart pub add dmx

This extension does three things.

1. It generates when you save

The dmx generator ships inside this extension, so there is nothing else to install. Open a Dart workspace and it starts watching: save a file and the generated members are rewritten; delete one by hand and it comes straight back. No terminal to keep open and no build command to remember.

The status bar shows $(eye) dmx while it is watching — click it for the log.

The extension looks for dmx in this order: the dmx.path setting, the copy bundled here, the workspace's own target/release/dmx and target/debug/dmx, then dmx on PATH. On a platform with no bundled copy, the universal build uses dmx from your PATH.

The extension stays off until you trust the folder, because it runs a program over the folder you opened and dmx.path can point at one inside it.

2. It shows you what is generated

The //#region divider is highlighted as a divider rather than as one more comment, so you can see where your code stops and the generated code starts. A divider you label yourself, such as //#region Helpers, is left alone — dmx never writes into one.

dmx annotations are highlighted in two tiers: the ones that generate code (@dmx('model'), @dmx('union'), @dmx('route'), …) apart from the ones that configure it (@dmx('key'), @dmx('check.…'), @dmx('query'), …). Dart's own annotations are left to Dart.

This works with whichever Dart extension you already have.

3. It highlights dmx templates

A dmx template is a .mustache file: Dart with Mustache tags in it. Both are highlighted, including tags inside Dart string literals, which is where templates put them constantly.

The Dart highlighting comes from your Dart extension. Without it, the tags still highlight and the Dart around them stays plain.

What generation looks like

@dmx('model')
class User {
  const User({required this.id, this.email, this.tags = const []});

  final String id;
  final String? email;
  final List<String> tags;

  //#region
  // fromJson, toJson, ==, hashCode, toString, copyWith — regenerated on save
  //#endregion
}

Decoding never throws. fromJson returns a result that names the field that failed — Order.lines[2].product.price — so a bad payload is a branch you handle rather than an exception you hope somebody caught.

Before writing, dmx checks that everything outside the divider is unchanged, and writes nothing at all when the generated code already matches.

Full documentation: dmx.dev/docs · github.com/Nimblesite/dmx