@lass-lang/bun-plugin-lass

Bun plugin for processing .lass files. Transforms Lass source to CSS via @lass-lang/core.

Installation

bun add @lass-lang/bun-plugin-lass --dev

Usage

With Bun.build()

import lass from "@lass-lang/bun-plugin-lass";

await Bun.build({
  entrypoints: ["./src/index.ts"],
  outdir: "./dist",
  plugins: [lass()],
});

With bunfig.toml (preload)

For automatic .lass support without explicit plugin configuration:

# bunfig.toml
preload = ["@lass-lang/bun-plugin-lass/preload"]

Then import .lass files directly:

import "./styles.lass";

CSS Modules

CSS Modules work with .module.lass files:

import styles from "./component.module.lass";

element.className = styles.container;

For TypeScript, add declarations:

// lass.d.ts
declare module "*.lass";

declare module "*.module.lass" {
  const classes: { readonly [key: string]: string };
  export default classes;
}

Options

lass({
  verbose: true,  // Enable logging (default: false)
});

Limitations

• No HMR: Bun's plugin API doesn't support Hot Module Replacement. For development with HMR, use Vite with @lass-lang/vite-plugin-lass.

How It Works

1. Plugin intercepts .lass file imports via onResolve/onLoad
2. Transpiles Lass source to JS module via @lass-lang/core
3. Executes JS to extract CSS string
4. Returns CSS to Bun's bundler with loader: "css"
5. For .module.lass: resolves to virtual .lass.module.css path so Bun applies CSS Modules scoping

Peer Dependencies

• bun >=1.0.0

License

MIT