vite-plugin-unused-code

0.1.8 verified Mon Apr 27 auth: no javascript

A Vite/Rollup plugin to detect unused files and unused exports in used files (dead code elimination analysis). Current stable version is 0.1.8, released March 2026, with frequent bug fixes and Vite 8/Rolldown compatibility updates. Ported from webpack-deadcode-plugin; uses micromatch patterns for file matching. Key differentiator: provides both unused file and unused export detection in a single plugin for Vite/Rollup ecosystems. Limitations: cannot detect unused CSS or TypeScript types, and unused exports will not be reported in Rolldown (Vite 8+).

Common errors

error TypeError: (0 , vite_plugin_unused_code.default) is not a function ↓

cause Using CommonJS require() on an ESM-only package.

fix

Use import statement: import unusedCode from 'vite-plugin-unused-code'

error Error: The plugin 'vite-plugin-unused-code' is not compatible with Vite 8. Please upgrade to a newer version. ↓

cause Using an older version of the plugin with Vite 8 (Rolldown).

fix

Upgrade to vite-plugin-unused-code >=0.1.7

error The exclude option is deprecated and will be removed in a future version. Use micromatch negation patterns instead. ↓

cause Using the deprecated 'exclude' option.

fix

Replace exclude with patterns: patterns: ['**/*.ts', '!ignore/**']

Warnings

gotcha Cannot detect unused CSS or TypeScript type exports – only JavaScript/TypeScript runtime exports are checked. ↓

fix Manually review or use additional tools (e.g., PurgeCSS, ts-prune) for CSS and type unused detection.

breaking Rolldown (Vite 8+) does not report removed exports during tree shaking; unused exports will never be shown. ↓

fix Use detectUnusedFiles only, or downgrade to Vite 7 or earlier for unused export detection.

deprecated The 'exclude' option is deprecated; use micromatch negation patterns in 'patterns' instead. ↓

fix Replace exclude with patterns like ['!excluded/**'].

gotcha Files matched by patterns are only considered unused if they have no imports or are not referenced. Dynamic imports (import()) may not be fully tracked. ↓

fix Verify detection results manually for dynamic imports.

Install

npm install vite-plugin-unused-code

yarn add vite-plugin-unused-code

pnpm add vite-plugin-unused-code

Imports

default (unusedCode)
wrong
```
const unusedCode = require('vite-plugin-unused-code')
```
correct
```
import unusedCode from 'vite-plugin-unused-code'
```
ESM-only package; CommonJS require() will fail. Use dynamic import() if needed.

VitePluginUnusedCodeOptions

wrong

import { VitePluginUnusedCodeOptions } from 'vite-plugin-unused-code'

correct

import type { VitePluginUnusedCodeOptions } from 'vite-plugin-unused-code'

Type import only; not a runtime export.

default export with options
wrong
```
unusedCode.new({ patterns: ['src/**/*.*'] })
```
correct
```
unusedCode({ patterns: ['src/**/*.*'] })
```
The default export is a function that accepts an options object. No constructor or new keyword.

Quickstart

Shows how to import and configure vite-plugin-unused-code in a Vite config file with commonly used options.

// vite.config.js
import { defineConfig } from 'vite';
import unusedCode from 'vite-plugin-unused-code';

export default defineConfig({
  plugins: [
    unusedCode({
      patterns: ['src/**/*.*'],
      exclude: ['src/legacy/**'],
      detectUnusedFiles: true,
      detectUnusedExport: true,
      failOnHint: false,
      exportJSON: false,
      log: 'unused',
    }),
  ],
});