Installation

caution

Jess is in early alpha, so features and syntax are likely to change!

If you just want to compile a file and keep moving, use install-on-demand:

npx --yes --package jess jess my-file.jess my-file.css

pnpm --package=jess dlx jess my-file.jess my-file.css

For real project work, install locally:

pnpm add -D jess

Then use the local CLI from your package scripts:

{
  "scripts": {
    "build:styles": "jess src/app.less dist/app.css",
    "lint:styles": "jess lint \"src/**/*.{css,less,scss,jess}\" --max-warnings 0"
  }
}

jess <input> [output] compiles. jess lint reports diagnostics without writing CSS.

Bundlers

rollup-plugin-jess is available and compiles .jess files through the current Jess compiler.
Webpack-specific integration is still evolving.

That split is intentional: stable core path first, then framework/bundler ergonomics on top.

Bundlers​

Bundlers