rollup-plugin-unused

0.1.1 verified Mon Apr 27 auth: no javascript

Rollup plugin that identifies source files not imported during a build, helping keep repositories clean. Version 0.1.1 (latest) released 2021-12-30, with low release cadence. Supports customization via extensions, include/exclude globs. Ships TypeScript definitions. Distinct from similar plugins (e.g., rollup-plugin-unused-files) by its minimal configuration and focus on detection rather than removal.

Common errors

error Error: Could not resolve entry module (index.js) ↓

cause rollup.config.js missing input or wrong path

fix

Ensure input points to your entry file, e.g., input: 'src/index.js'

error TypeError: findUnused is not a function ↓

cause Using named import instead of default import

fix

Use 'import findUnused from 'rollup-plugin-unused'' instead of 'import { findUnused } from ...'

Warnings

gotcha Plugin must be added before any other plugins that load files (e.g., @rollup/plugin-babel) to correctly detect unused imports. ↓

fix Place findUnused() as the first plugin in the plugins array.

gotcha By default, plugin looks for source files with extension .js in the ./src/ folder. Files with other extensions or in other directories are ignored unless configured. ↓

fix Use 'extensions' option for additional file types, 'include' option for a custom glob pattern.

gotcha 'include' option overrides 'extensions' option. If both are specified, only 'include' is used. ↓

fix Use either 'include' or 'extensions', not both, unless you understand the override behavior.

deprecated No known deprecations for this package.

Install

npm install rollup-plugin-unused

yarn add rollup-plugin-unused

pnpm add rollup-plugin-unused

Imports

findUnused

wrong

const findUnused = require('rollup-plugin-unused')

correct

import findUnused from 'rollup-plugin-unused'

Package exports a single default function. Use ESM import as shown.

findUnused with options

wrong

import { findUnused } from 'rollup-plugin-unused'

correct

import findUnused from 'rollup-plugin-unused';
findUnused({ extensions: ['.js', '.ts'], include: ['src/**/*.mjs'], exclude: ['src/legacy/*.js'] })

Options are passed directly to the default export. Named import not supported.

Plugin usage in Rollup config

wrong

plugins: [require('rollup-plugin-unused')()]

correct

import findUnused from 'rollup-plugin-unused';
export default { input: 'index.js', plugins: [findUnused()] }

Use ESM import; require() may work but is not official. Plugin must be placed before other plugins.

Quickstart

Demonstrates basic usage detecting unused .js files in src/ directory during a Rollup build.

import findUnused from 'rollup-plugin-unused';
import resolve from '@rollup/plugin-node-resolve';

// rollup.config.js
export default {
  input: 'src/index.js',
  output: { file: 'dist/bundle.js', format: 'cjs' },
  plugins: [
    // Must come before any source-loading plugins
    findUnused({ extensions: ['.js'] }),
    resolve()
  ]
};