Simple, clean, and automatic bundling of your Node modules and packages for use in the browser.
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jsbundle -- Node.JS modules for the browser

jsbundle takes your Node modules and makes them work in the browser.

It finds all require calls in your code and includes the necessary module files. Then, it wraps all these modules using the Node variant of CommonJS module headers.

It handles node_modules directories and package.json files just like Node does.

It comes with a "Dev CDN" that will watch your files for changes and serve the latest jsbundled version of your code via local HTTP.

It has good error handling and will probably do what you want without any configuration.



npm install -g jsbundle

Or clone this repo, then from the repo dir, run:

npm link
npm install


From your Node package's directory, run:

jsbundle .

Just for fun, you can try it out with minification:

npm install -g uglify-js
jsbundle | uglifyjs --unsafe --lift-vars --consolidate-primitive-values

You can also pipe this to node:

jsbundle 2>/dev/null | uglifyjs --unsafe --lift-vars --consolidate-primitive-values | node

which should give you the exact same output as:

node .

More Detailed Usage Instructions


[JSBUNDLE_ENV=<env>] jsbundle <node_package_dir> [--bundle-url=bundle_url]

Create a bundle from the node package contained in node_package_dir.

If the node_package_dir contains a "jsbundle.json", that file will be used to configure jsbundle's operation.

The entry file jsbundle will use to start bundling is one of (in decreasing order of precedence):

  • the "entryFile" defined in the "jsbundle.json" file
  • the "main" file defined in the node package's "package.json"
  • the node package's "index.js" file

Specifying a bundle_url will override any bundle URL defined in the config file. This is useful for versioning/cache busting.

The JSBUNDLE_ENV environment variable determines how the config file is evaluated (see below).

This command is basically equivalent to running:

node <node_package_dir>

in the sense that when the resulting script is executed in the browser, the package at node_package_dir will be the first to execute.

For production deployment, you'll probably want to pipe the resulting output to the JavaScript minifier of your choice.

Configuration and JSBUNDLE_ENV

Example Config

  "defaults": {
    "mangleNames": false,

  "production": {
    "mangleNames" true

jsbundle uses the "defaults" configuration as a base, and then, depending on the value of the JSBUNDLE_ENV environment variable, overrides or adds more values.

In the example above, if the value of JSBUNDLE_ENV is "production", module names will be mangled.

See the included jsbundle.json for an annotated example of all configuration options.

Loading External Scripts (Like CDN Hosted jQuery) with module.externalDependency

In any of your modules that are browser-only, you can easily add external dependencies that are guaranteed to be loaded before your code executes by using the module.externalDependency function.


Note that the URL you pass to this function must be a constant string.

Multiple calls to module.externalDependency will load any given script URL only once. However, it only does naive string matching, so:


will load jQuery twice. To avoid bugs caused by typos, it's advisable to create a wrapper module around each external script you load and then load the wrapper module in the rest of your code. For example:


module.exports = $.noConflict(true);


var $ = require('./jquery');
// etc...

If you execute a bundle with external dependencies without a DOM (e.g. in node.js), the dependencies will be silently ignored.

Mocking / Stubbing Modules

In order to make unit testing your modules easier, jsbundle provides a mocking API:

module.mock('some-module-name.js', { my: 'mock module.exports object' });
var someModule = require('../path/to/some-module-name.js');
// test code here
  • module.mock(moduleIdSubstring, mockExportsObject) takes a string as its first parameter and an arbitrary object as its second parameter. After calling module.mock, all require calls thereafter will return the mockExportsObject if the required module's ID matches the moduleIdSubstring. Note that if you specified mangleNames: true, the module ID is a somewhat unpredictable mangled numeric name, so it is not recommended to use module.mock with mangleNames turned on.

  • module.unmock(moduleIdSubstring) disables a previous call to module.mock. The moduleIdSubstring must match the one from the corresponding module.mock call exactly.

For integration testing, you'll want to define mocks before loading the bundle by using the global variable jsbundleMocks:

  window.jsbundleMocks = {
    'some-module-name.js': { my: 'mock module.exports object' }
<script src="/path/to/my/bundle.js"></script>

You can still module.unmock later on in your test code:


Again, make sure the strings match exactly.


[JSBUNDLE_ENV=<env>] devcdn [port]

Start a "Dev CDN" bundle HTTP server.

The Dev CDN will run on the port specified in the config file, or 8081 if none is specified.

The Dev CDN finds all package.json files below the directory from which it is executed and can serve these as bundles. Bundle names are taken from the "name" field of the package.json file, with ".js" appended. node_modules directories are ignored. So, if you run the Dev CDN from a package directory with the "name" of example and on the default port, you can request the bundled package at the URL: http://localhost:8081/example.js.

You can specify the JSBUNDLE_ENV (see below) either via an environment variable or by passing a value to the --env flag. The JSBUNDLE_ENV will be used to evaluate and jsbundle.json files encountered in the served packages.


[JSBUNDLE_ENV=env] jsbundle-s3 <node_package_dir> [--dry-run] [--no-minify] [--version-salt=<version_salt>]

Minify and upload your JS code to Amazon's Simple Storage Service (S3).

The options are basically identical to the jsbundle options, with some minor differences:

  1. the --dry-run option, which will run everything except the actual S3 upload.
  2. the --no-minify option, which will turn off minification.
  3. the --version-salt option, which will salt the version hash, for the paranoid.
  4. the "s3" key in jsbundle.json, which is as follows:
<pre>"s3": {
  "accessKeyId": "my_access_key_id",
  "secretAccessKey": "my_secret_access_key",
  "bucketName": "my_bucket",
  "afterUpload": "redis-cli hmset jsbundle.urls $NAME $URL"

afterUpload is optional, and runs a shell command with 3 variables set after S3 upload succeeds:

  • $NAME — the file name (taken from the bundled package's package.json or directory name), e.g.: mypackage.js
  • $VERSION — the sha1 version string, e.g.: 7f2da1cf914bd863068224aa1c10e2ba3a4bd0b0
  • $URL — the url, without a protocol, of the uploaded file, e.g.: //


Test coverage is currently mediocre. You can run tests with:

npm test


  • All values passed to require in your code must be string literals. Otherwise, jsbundle wouldn't be able to reliably find all the modules to include in the bundled output.

  • The special variable __filename is equal to the If you specify the mangleNames option (see below), then the __filename will be the mangled numeric id of the module.

  • The special variable __dirname doesn't really make sense in the context of browser modules, so while the variable exists, its value is undefined.

Thanks To