rollup-plugin-output-size

2.0.0 verified Mon Apr 27 auth: no javascript

A Rollup plugin that displays output bundle sizes (uncompressed and gzipped) for assets, chunks, and entries. Current stable version is 2.0.0, released 2025, with peer dependency on Rollup ^2.0.0 || ^3.0.0 || ^4.0.0. Ships TypeScript types. Key differentiators: lightweight (zero dependencies since v2.0.0), uses Node.js built-in gzip and util.styleText, provides customization options (bytes, hide, gzip, silent, summary, handle), and exports utility functions (format, summarize). Actively maintained, with breaking changes in v2.0.0 requiring Node >=20.12.0 and removal of deprecated RollupOutputSizeOptions interface.

Common errors

error Error [ERR_REQUIRE_ESM]: require() of ES Module ↓

cause Using CommonJS require() on an ESM-only package v2.0.0

fix

Switch to ESM (import outputSize from 'rollup-plugin-output-size') or use dynamic import()

error TypeError: outputSize is not a function ↓

cause Using default import from CommonJS require but did not destructure .default

fix

const outputSize = require('rollup-plugin-output-size').default;

error TypeError: (0 , plugin_1.default) is not a function ↓

cause Incorrect import of default export when using TypeScript and CommonJS

fix

Use import outputSize from 'rollup-plugin-output-size'

error Cannot find module 'node:util' or 'node:zlib' ↓

cause Node.js version <20.12.0 missing required built-in APIs

fix

Update Node.js to >=20.12.0

Warnings

breaking Requires Node.js >=20.12.0 in v2.0.0 ↓

fix Update Node.js to 20.12.0 or later

deprecated RollupOutputSizeOptions interface removed in v2.0.0 ↓

fix Replace with Options interface (import type { Options } from 'rollup-plugin-output-size')

gotcha CommonJS require returns { default: outputSize } not outputSize directly ↓

fix Use ESM import or destructure: const { default: outputSize } = require('rollup-plugin-output-size')

gotcha Summary total gzip size is sum of individual gzip sizes, not archive-level ↓

fix Use archiver for accurate total gzip size

gotcha Options type not available as runtime value; only as TypeScript type import ↓

fix Import type: import type { Options } from 'rollup-plugin-output-size'

deprecated RollupOutputSizeOptions interface deprecated since v1.4.0 and removed in v2.0.0 ↓

fix Use Options interface

Install

npm install rollup-plugin-output-size

yarn add rollup-plugin-output-size

pnpm add rollup-plugin-output-size

Imports

outputSize (default)

wrong

const outputSize = require('rollup-plugin-output-size')

correct

import outputSize from 'rollup-plugin-output-size'

ESM-only since v2.0.0; CommonJS require returns { default: outputSize }

format

wrong

const { format } = require('rollup-plugin-output-size'); // works in CJS but preferred ESM

correct

import { format } from 'rollup-plugin-output-size'

Named export for utility function; available in both ESM and CJS via the package's dual format

summarize

wrong

import summarize from 'rollup-plugin-output-size'

correct

import { summarize } from 'rollup-plugin-output-size'

Named export, not default; used for custom summary output

Options

wrong

import { Options } from 'rollup-plugin-output-size' // Value not exported at runtime

correct

import type { Options } from 'rollup-plugin-output-size'

TypeScript type only; do not import as value

Quickstart

Shows full configuration with all options and custom handle callback using format utility.

import outputSize from 'rollup-plugin-output-size';
import { format, summarize } from 'rollup-plugin-output-size';

export default {
  input: 'src/index.js',
  output: { dir: 'dist' },
  plugins: [
    outputSize({
      bytes: true,
      gzip: ['chunk', 'entry'],
      hide: false,
      silent: false,
      summary: true,
      handle(info) {
        console.log(format(info));
      }
    })
  ]
};