rollup-plugin-analyzer

4.0.0 verified Mon Apr 27 auth: no javascript

Rollup plugin that prints detailed bundle analysis metrics to the console, including bundle size, original size, code reduction percentage, module count, and per-file breakdown with rendered size, original size, relative contribution, and dependents. Version 4.0.0 supports Rollup 2.x/3.x. Outputs formatted tables and optional summary-only view. Useful for CI gating via onAnalysis callback. Differentiators include zero dependencies, optional CI integration, and summaryOnly mode for concise output.

Common errors

error Error [ERR_REQUIRE_ESM]: require() of ES Module [...] from [...] not supported. ↓

cause Node.js trying to require an ESM module when using require() with type: 'module' or .mjs files.

fix

Use import instead of require() in your rollup config, or rename file to .cjs.

error TypeError: analyze is not a function ↓

cause Using named import { analyze } instead of default import.

fix

Use: import analyze from 'rollup-plugin-analyzer' (no braces).

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

cause Package not installed or not in node_modules.

fix

Run: npm install --save-dev rollup-plugin-analyzer

Warnings

breaking Version 4.0.0 drops support for Rollup < 2.x. Ensure you are using Rollup 2 or higher. ↓

fix Upgrade to Rollup 2.x or later, or pin to rollup-plugin-analyzer@3.x.

gotcha The module counts rendered size (after tree-shaking), not original size. Be aware when comparing numbers. ↓

fix Read documentation: rendered size is post-tree-shaking; original size is before.

deprecated The `entry` and `dest` options in the example are for Rollup < 1.x. Modern Rollup uses `input` and `output`. ↓

fix Use `input` and `output` per Rollup 1.x+ API. Example in README may be outdated.

gotcha If using ESM in Node.js (e.g., type: 'module'), ensure your config file uses .mjs extension or dynamic import for CJS plugins. ↓

fix Rename config to rollup.config.mjs or use createRequire from 'module'.

Install

npm install rollup-plugin-analyzer

yarn add rollup-plugin-analyzer

pnpm add rollup-plugin-analyzer

Imports

default (analyze)

wrong

import { analyze } from 'rollup-plugin-analyzer'

correct

import analyze from 'rollup-plugin-analyzer'

Default export only. Named import will result in undefined.

default (analyze) via require
```
const analyze = require('rollup-plugin-analyzer')
```
CJS require style, works in Node.js < 12 or when type: 'commonjs' is set.

onAnalysis callback

wrong

import { onAnalysis } from 'rollup-plugin-analyzer'

correct

import analyze from 'rollup-plugin-analyzer';
analyze({ onAnalysis: ({ bundleSize }) => { /* ... */ } })

onAnalysis is an option, not a separate export. Pass it as a property.

Quickstart

Configure rollup-plugin-analyzer with summary-only output, limiting to top 10 modules, filtering out node_modules, and calling onAnalysis callback for custom reporting.

// rollup.config.js
import analyze from 'rollup-plugin-analyzer';

export default {
  input: 'src/index.js',
  output: {
    file: 'dist/bundle.js',
    format: 'cjs'
  },
  plugins: [
    analyze({
      summaryOnly: true,
      limit: 10,
      filter: (module) => !module.includes('node_modules'),
      onAnalysis: ({ bundleSize, moduleCount }) => {
        console.log(`Bundle size: ${bundleSize} bytes, modules: ${moduleCount}`);
      }
    })
  ]
};