rollup-pluginutils

2.8.2 verified Mon Apr 27 auth: no javascript maintenance

Utility functions commonly needed by Rollup plugins, including file filtering (createFilter), scope analysis (attachScopes), identifier sanitization (makeLegalIdentifier), data-to-ESM conversion (dataToEsm), and extension handling (addExtension). This package is at version 2.8.2 and is stable but in maintenance mode; it has been superseded by `@rollup/pluginutils` for Rollup >= 1.0. TypeScript type definitions are included. Unlike ad-hoc implementations, these utilities are optimized for Rollup's plugin lifecycle and AST walking.

Common errors

error Cannot find module 'rollup-pluginutils' ↓

cause Package not installed or incorrect import path

fix

Run npm install rollup-pluginutils@2.8.2 or if using newer Rollup, install @rollup/pluginutils.

error TypeError: createFilter is not a function ↓

cause Default import used instead of named import

fix

Change import createFilter from 'rollup-pluginutils' to import { createFilter } from 'rollup-pluginutils'.

error Error: Could not resolve 'estree-walker' ↓

cause Missing peer dependency estree-walker

fix

Run npm install estree-walker or ensure it is in dependencies.

error Error: AttachScopes requires an AST and identifier (like 'scope') ↓

cause attachScopes called with missing or incorrect arguments

fix

Ensure the second argument is a string property name to attach, e.g., attachScopes(ast, 'scope').

Warnings

deprecated rollup-pluginutils is deprecated in favor of @rollup/pluginutils ↓

fix Replace rollup-pluginutils with @rollup/pluginutils and update imports (e.g., import { createFilter } from '@rollup/pluginutils').

breaking createFilter signature changed with the addition of options object (resolve option) in v2.0.0 ↓

fix If migrating from v1, pass {resolve: string} as third argument instead of a string directly. Updated docs: createFilter(include, exclude, {resolve: '/path'}).

gotcha attachScopes modifies the AST in place and expects estree-walker compatibility; it does not work with ASTs from other parsers. ↓

fix Ensure the AST is produced by acorn (Rollup's default parser) or a compatible parser that uses the same node types.

deprecated attachScopes may be removed in future major versions; consider using @rollup/pluginutils which provides similar functionality ↓

fix Migrate to @rollup/pluginutils and use its attachScopes function.

breaking dataToEsm namedExports option changed behavior in v2.0.0, defaulting to true instead of false ↓

fix If you relied on namedExports being false by default, explicitly set it to false in options.

gotcha makeLegalIdentifier does not guarantee uniqueness for all patterns; collisions can occur. ↓

fix Do not rely on makeLegalIdentifier for generating unique identifiers; it only converts non-legal characters to underscores.

deprecated Version 2.8.2 is the last release; no further updates will be published to this package. ↓

fix Switch to @rollup/pluginutils for continued maintenance.

Install

npm install rollup-pluginutils

yarn add rollup-pluginutils

pnpm add rollup-pluginutils

Imports

createFilter
wrong
```
const createFilter = require('rollup-pluginutils').createFilter
```
correct
```
import { createFilter } from 'rollup-pluginutils'
```
Named import; avoid default import. This package supports both ESM and CJS, but ESM is recommended.

addExtension

wrong

import addExtension from 'rollup-pluginutils'

correct

import { addExtension } from 'rollup-pluginutils'

Named import; addExtension is not a default export.

attachScopes

wrong

const attachScopes = require('rollup-pluginutils/attachScopes')

correct

import { attachScopes } from 'rollup-pluginutils'

Named import; subpath imports are not supported.

dataToEsm

wrong

import { dataToEsm } from 'rollup'

correct

import { dataToEsm } from 'rollup-pluginutils'

Named import; this function is not part of Rollup core.

Quickstart

Demonstrates using createFilter to include only files under src/ and exclude node_modules, then applying a simple transform.

import { createFilter } from 'rollup-pluginutils';
import { rollup } from 'rollup';

const filter = createFilter(['src/**'], ['node_modules/**']);

async function build() {
  const bundle = await rollup({
    input: 'src/index.js',
    plugins: [{
      name: 'example',
      transform(code, id) {
        if (!filter(id)) return null;
        // transform code
        return code.replace(/__VERSION__/g, '1.0.0');
      }
    }]
  });
  await bundle.write({ file: 'dist/bundle.js', format: 'es' });
}

build().catch(err => console.error(err));