Mono Bundler

1.43.92 verified Sat Apr 25 auth: no javascript

Monorepo bundler based on rollup.js and vercel/ncc. Current stable version 1.43.92 supports configurable workspace packages, loader file generation, hash file names, and legacy browser support via Babel polyfills. It wraps rollup and ncc to provide a unified configuration for monorepos with glob-based package discovery. Maintained by hoevelmanns. Release cadence is irregular; latest version from 2024. Differentiator: bundler integration for monorepos that avoids manual per-package rollup configs, but remains experimental and may lack community adoption compared to tools like Nx or Turborepo.

Common errors

error Error: Cannot find module 'mono-bundler' ↓

cause Package not installed or ESM resolution issue.

fix

Run npm install mono-bundler and ensure package.json has 'type': 'module'.

error TypeError: monoBundler is not a function ↓

cause Imported via require() but package is ESM-only.

fix

Change to import monoBundler from 'mono-bundler' and use ESM context.

error Error: The 'legacyBrowserSupport' option is deprecated. Please configure Babel manually. ↓

cause Using deprecated legacyBrowserSupport option.

fix

Remove legacyBrowserSupport from config and add @rollup/plugin-babel.

Warnings

breaking The package is experimental; breaking changes may occur without major version bump. ↓

fix Lock to patch version and review changelog before upgrading.

deprecated legacyBrowserSupport option will be removed in v2.0.0; use babel config directly. ↓

fix Remove legacyBrowserSupport and add @rollup/plugin-babel manually.

gotcha Requires Node >=10, but some features need Node >=14 due to ESM usage. ↓

fix Use Node >=14 when using ESM imports or modern rollup plugins.

gotcha hashFileNames generates long hashes; clear cache after each build to avoid stale files. ↓

fix Run `rm -rf dist` before each build or use rollup's 'clean' output option.

gotcha When using pnpm workspaces, glob patterns may not find packages correctly. ↓

fix Use absolute paths or relative from root; consider using 'packages: ['.']' as fallback.

Install

npm install mono-bundler

yarn add mono-bundler

pnpm add mono-bundler

Imports

default
wrong
```
const monoBundler = require('mono-bundler')
```
correct
```
import monoBundler from 'mono-bundler'
```
ESM-only; will error with require() due to missing default export in Node <14 or CJS context
defineConfig
```
import { defineConfig } from 'mono-bundler'
```
Helper to define configuration with TypeScript type inference
BundleConfig
wrong
```
import { BundleConfig } from 'mono-bundler'
```
correct
```
import type { BundleConfig } from 'mono-bundler'
```
Type-only import; using value import will fail at runtime because BundleConfig is not a value

Quickstart

Shows minimal mono.config.js with package globs, loaders, and rollup output options; run with `mono -c`

// mono.config.js
export default {
  packages: ['packages/*'],
  createLoaders: true,
  hashFileNames: true,
  legacyBrowserSupport: false,
  plugins: [],
  // rollup input
  input: 'src/index.js',
  output: {
    dir: 'dist',
    format: 'esm'
  }
};
// Run: mono -c