rollup-plugin-pure

0.4.0 verified Mon Apr 27 auth: no javascript

Rollup/Vite plugin that automatically injects /*#__PURE__*/ annotations before specific function calls and /*@__NO_SIDE_EFFECTS__*/ before function declarations, enabling better tree-shaking for libraries with definition functions like Vue's defineComponent. Current stable version is 0.4.0, actively maintained. Supports regex function names, uses AST-based approach, and handles Rollup's awareness of pure annotations. Key differentiator: automatic annotation injection without manual marks, works with Vite and Rollup 3/4.

Common errors

error Plugin 'rollup-plugin-pure' does not provide a default export, but a named export 'PluginPure' is available. ↓

cause Default import used instead of named import.

fix

Use import { PluginPure } from 'rollup-plugin-pure' instead.

error TypeError: PluginPure is not a constructor ↓

cause PluginPure is a function (factory), not a class. Calling new PluginPure() fails.

fix

Call PluginPure({...}) without new.

error Error: Must specify at least one function name or regex in 'functions' option ↓

cause Missing or empty functions array in configuration.

fix

Provide an array of function names or regex patterns in the functions option.

Warnings

breaking Plugin name changed in v0.3.0 from 'rollup-plugin-pure' to 'PluginPure' export ↓

fix Update import to correctly use named export PluginPure.

breaking AST-based approach introduced in v0.3.0; old RegExp-based approach removed ↓

fix Migrate to new configuration; see changelog for details.

gotcha When Rollup already marks a function as pure, the plugin may not add an annotation, leading to no effect ↓

fix Check if Rollup's built-in pure detection covers your functions; if not, adjust your configuration.

deprecated Support for Rollup <3.0 may be dropped in future versions ↓

fix Upgrade to Rollup 3 or 4.

gotcha Using `include` glob may not match expected files if patterns conflict with `exclude` ↓

fix Test patterns in the playground or use more specific include/exclude rules.

Install

npm install rollup-plugin-pure

yarn add rollup-plugin-pure

pnpm add rollup-plugin-pure

Imports

PluginPure

wrong

import PluginPure from 'rollup-plugin-pure'

correct

import { PluginPure } from 'rollup-plugin-pure'

Named export; default import is not available.

PluginPure as rollupPluginPure

wrong

const rollupPluginPure = require('rollup-plugin-pure').PluginPure;

correct

import { PluginPure as rollupPluginPure } from 'rollup-plugin-pure'

CommonJS users should use destructured require; ESM is also supported.

PluginPure type

wrong

import { PluginPure } from 'rollup-plugin-pure'

correct

import type { PluginPure } from 'rollup-plugin-pure'

Type-only import is safe but not required; PluginPure is also a runtime value.

Quickstart

Configures Vite to annotate defineComponent and regex-matched functions as pure, targeting files ending with 'pure.js' except those starting with 'im'.

// vite.config.ts
import { PluginPure } from 'rollup-plugin-pure';
import { defineConfig } from 'vite';

export default defineConfig({
  plugins: [
    PluginPure({
      functions: ['defineComponent', /^define(Page|Meta)$/],
      include: [/(?<!im)pure\.js$/],
      // exclude: [],
      // sourcemap: true,
    }),
  ],
});