browser-pack-flat

3.5.0 verified Mon Apr 27 auth: no javascript maintenance

Browserify plugin that bundles modules into a single scope, similar to Rollup, eliminating the require runtime wrapper. Current stable version is 3.5.0. Maintained sporadically; no major release since 2020. Differentiator: drastically reduces bundle size and execution overhead by rewriting require() calls to variable references and flattening module scopes. Unlike default browser-pack, it removes the per-module function wrapper and runtime, at the cost of potential execution order differences and incompatibility with certain patterns (e.g., wrapped require, factor-bundle). Supports an ecmaVersion option and IIFE removal via iife:false.

Common errors

error Error: Cannot find module 'browser-pack-flat/plugin' ↓

cause Old v3.0.x path; main entry acts as plugin since v3.1.0.

fix

Use require('browser-pack-flat') instead of '/plugin'.

error Unexpected token: punc ()) ↓

cause Input is not browser-unpack JSON but raw JavaScript bundle.

fix

Pipe through browser-unpack first: browserify app.js | browser-unpack | browser-pack-flat

error TypeError: browserify(...).plugin is not a function ↓

cause Forgetting to call .plugin() with the function; passing string instead.

fix

Use .plugin(packFlat) or .plugin(require('browser-pack-flat'))

Warnings

gotcha Modules are executed fully one after another, not inline. This can change execution order vs Node.js and default browserify. ↓

fix Ensure modules don't rely on interleaved execution; test thoroughly.

gotcha Does not work with factor-bundle; output splitting is incompatible. ↓

fix Use a different bundling strategy if you need code splitting.

gotcha Modules that wrap require() (e.g., with custom caching or instrumentation) will break. ↓

fix Avoid wrapping require; use inline requires only.

breaking In v3.4.0, conditional and lazy require() calls are no longer inlined; they remain as function calls. ↓

fix If you need inlining of dynamic requires, pin to earlier version.

Install

npm install browser-pack-flat

yarn add browser-pack-flat

pnpm add browser-pack-flat

Imports

default
wrong
```
const packFlat = require('browser-pack-flat')
```
correct
```
import packFlat from 'browser-pack-flat'
```
Package ships as CommonJS, so both import and require work. The module.exports is a function, so default import is safe.
plugin (via browserify)
wrong
```
browserify -p browser-pack-flat/plugin
```
correct
```
browserify -p browser-pack-flat
```
Since v3.1.0, the main entry also serves as the plugin. Using the /plugin path still works but is unnecessary.
require as packer
wrong
```
browserify(...).plugin(require('browser-pack-flat/plugin'), { ... })
```
correct
```
browserify(...).plugin(packFlat, { ... })
```
The plugin function is the default export; direct require of the package works. Use .plugin() method, not .transform().
CLI usage via browser-unpack
wrong
```
browserify app.js | browser-pack-flat
```
correct
```
browserify app.js | browser-unpack | browser-pack-flat
```
The packer expects browser-unpack JSON on stdin, not a raw bundle. Must pipe through browser-unpack first.

Quickstart

Demonstrates using browser-pack-flat as a browserify plugin with IIFE removal, piping output to a file.

const browserify = require('browserify');
const packFlat = require('browser-pack-flat');
const fs = require('fs');

const b = browserify({ entries: './app.js' });
b.plugin(packFlat, { iife: false });
b.bundle()
  .pipe(fs.createWriteStream('bundle.js'))
  .on('finish', () => console.log('Bundled!'));