browserify-dev-bundler

2.0.0 verified Sat Apr 25 auth: no javascript maintenance

On-demand browserify bundler middleware for development with watchify support. Version 2.0.0 is the latest stable release, with low release cadence (last release in 2016). It dynamically bundles CommonJS modules via HTTP requests, caching bundles with watchify for fast responses during development. Unlike manual watchify tasks or file-based bundling, it integrates directly as Express middleware, intercepting *.js requests and bundling on the fly. Not suitable for production—use browserify build process instead. Works with Node.js and Express.

Common errors

error Cannot find module 'browserify' ↓

cause Missing peer dependency browserify; not automatically installed with npm install.

fix

Run: npm install browserify watchify --save-dev

error bundler.middleware is not a function ↓

cause Forgetting to instantiate DevBundler with new; calling DevBundler() without new returns a constructor, not an instance.

fix

Use: const bundler = new DevBundler(options); or simply DevBundler(options) (works without new due to internal check).

Warnings

gotcha Middleware matches all *.js files by default; may unintentionally bundle non-module JS files or cause conflicts with static file serving. ↓

fix Use a regex pattern to restrict which URLs are bundled: e.g., bundler.middleware(/^\/js\/(.+)\.js$/).

deprecated watchify is enabled by default, which may cause high memory usage in large projects or when many files change. ↓

fix Set watchify: false if you don't need auto-rebundling, or manually manage watchify instances.

breaking Version 2.0.0 changed the default middleware behavior to intercept all *.js; previous versions used a different default pattern. ↓

fix Update regex patterns if you relied on older defaults; use bundler.middleware(/^\/js\/(.+)\.js$/) to restrict paths.

gotcha addFile option overrides default bundle.add(); using bundle.require() without expose can cause double bundling or missing dependencies. ↓

fix Ensure addFile function uses bundle.require() with expose option for modules that need to be requireable by other bundles.

gotcha bundle-error event does not prevent crashes; unhandled errors may crash the server. ↓

fix Always attach a listener to 'bundle-error' event: bundler.on('bundle-error', err => console.error(err)).

Install

npm install browserify-dev-bundler

yarn add browserify-dev-bundler

pnpm add browserify-dev-bundler

Imports

DevBundler

wrong

import DevBundler from 'browserify-dev-bundler';

correct

const DevBundler = require('browserify-dev-bundler');

CJS-only package; no ESM exports. Default export is the constructor.

middleware
wrong
```
app.use(DevBundler.middleware);
```
correct
```
app.use(bundler.middleware());
```
middleware() returns a function; must be called on a DevBundler instance.

events

wrong

bundler.addEventListener('pre-bundle', ...);

correct

bundler.on('pre-bundle', (bundle, modName, modPath) => {});

Uses Node.js EventEmitter pattern; .on() not addEventListener.

Quickstart

Sets up an Express server with on-demand browserify bundling using the middleware.

const express = require('express');
const DevBundler = require('browserify-dev-bundler');
const path = require('path');

const app = express();
const bundler = DevBundler({
  root: path.join(__dirname, 'public', 'js'),
  watchify: true,
  debug: true,
  transforms: []
});

app.use(bundler.middleware());
app.listen(3000, () => console.log('Dev server on 3000'));

// Request GET /app.js => bundles public/js/app.js