rollup-plugin-jess

1.0.8-alpha.8 verified Mon Apr 27 auth: no javascript

Rollup plugin that compiles Jess CSS preprocessor files into JavaScript modules at build time. Currently at v1.0.8-alpha (alpha stage), with low release cadence. Requires Rollup ^2.0.0 as a peer dependency. Differentiators: dedicated integration for the Jess language, TypeScript declarations included. Alternatives like generic CSS rollup plugins (e.g., rollup-plugin-postcss) require additional configuration for custom syntaxes.

Common errors

error Error: Cannot find module 'rollup-plugin-jess' ↓

cause Plugin not installed or npm install incomplete.

fix

Run npm install rollup-plugin-jess --save-dev (or yarn equivalent) in project root.

error TypeError: jess is not a function ↓

cause Using CommonJS require in an ESM-only package; jess is the default export but not available via require as a function.

fix

Use dynamic import: const jess = (await import('rollup-plugin-jess')).default; in CommonJS context, or convert rollup.config.js to ES module.

error Error: Peer dependency rollup@^2.0.0 not installed ↓

cause Rollup is missing or version mismatch (e.g., Rollup 3.x installed).

fix

Install Rollup 2.x: npm install rollup@^2.0.0 --save-dev.

Warnings

deprecated Plugin is in alpha version (1.0.8-alpha). API may change without major version bump. ↓

fix Pin to exact version and monitor for breaking changes before production use.

gotcha Plugin expects Rollup ^2.0.0; incompatible with Rollup 3+. ↓

fix Do not use with Rollup 3+; consider using rollup-plugin-jess-ng fork or wait for update.

gotcha Requires Node.js >=12; older versions may cause cryptic module resolution errors. ↓

fix Upgrade Node.js to >=12 or use a transpiler for the plugin.

deprecated Jess framework itself (jesscss) may be deprecated; last release in 2019. Plugin depends on it. ↓

fix Evaluate alternative CSS preprocessors or ensure Jess is still maintained for your use case.

Install

npm install rollup-plugin-jess

yarn add rollup-plugin-jess

pnpm add rollup-plugin-jess

Imports

default export (jess)
wrong
```
const jess = require('rollup-plugin-jess');
```
correct
```
import jess from 'rollup-plugin-jess'
```
ESM only; CommonJS require will not work because the package is type: module and uses ESM syntax. For Rollup configs in CJS, use dynamic import: const jess = (await import('rollup-plugin-jess')).default;
jess (as named export)
wrong
```
import jess from 'rollup-plugin-jess'
```
correct
```
import { jess } from 'rollup-plugin-jess'
```
The plugin also exports a named export `jess` which is the same as default. Both work, but importing as default is more idiomatic due to single-function usage.
type JessOptions
wrong
```
import { JessOptions } from 'rollup-plugin-jess' (if used at runtime)
```
correct
```
import type { JessOptions } from 'rollup-plugin-jess'
```
TypeScript declaration ships with the package; JessOptions is exported as a named type for plugin configuration. Only import as type to avoid runtime inclusion.

Quickstart

Rollup configuration importing the jess plugin, converting Jess files in the build pipeline.

// rollup.config.js
import jess from 'rollup-plugin-jess';
import { defineConfig } from 'rollup';

export default defineConfig({
  input: 'src/main.js',
  output: {
    file: 'dist/bundle.js',
    format: 'esm'
  },
  plugins: [
    jess({
      // Jess configuration options (see jesscss.github.io)
      // e.g., compress: false
    })
  ]
});