minifyjs — A node minifier

minifyjs is a Javascript code minifier written for node. It's aim is flexibility.

Installation

minifyjs is an npm package. You should be able to install it using

npm install minifyjs

To install the minifyjs command, use

npm install -g minifyjs

This will install the current stable version. To install the latest development version, clone this repository and install it.

git clone git://github.com/clarkf/minifyjs.git
cd minifyjs
npm install -g

Congratulations! You're half way to the minified files of your dreams.

Use

You can use minifyjs from the command line.

minifyjs [arguments] [-b/m] [-i path/input.js] [-o path/output.js]

Possible arguments

-b or --beautify — Beautify code. The opposite of minifying code.
-m or --minify — Minify code. Available options for the minification engine
-e or --engine E — Specify an engine. If left unspecified, it defaults to 'best', for minification, or 'js-beautify' for beautification. For a list of available engines, see Engine section below.
-l I or --level I — Specify a minification level (does not apply to beautification). Generally, there are three levels available:
- 0 — Strips whitespace, leaves code intact (depending on engine)
- 1 — Simple optimizations. Changes code slightly without deep optimization. Probably what you'll want for most code.
- 2 — Advanced optimizations.
-o or --output — Write data to a specific file instead of outputting to STDOUT.

The concept here is for use within larger projects. You can easily integrate this into your workflow using:

minifyjs -m mycode.js > mycode.min.js

This will create a file called mycode.min.js containing the smallest minified version available (see best engine explanation below).

Or, with a specific engine:

minifyjs -m -e uglify mycode.js

Or, beautify with a specific engine:

minifyjs -b -e js-beautify mycode.js

Engines

Minification engines

Currently, minifyjs only supports two engines for minification:

uglify — Mihai Bazon's amazing UglifyJS2.
gcc — Google Closure Compiler via Tim Smart's node-closure. See their API Reference for details.
yui — YUI Compressor. This is currently done through Tim Smart's node-yui-compressor module. Currently, minification levels are ignored.
best — Custom engine which calls all other engines and compares their output. It finds the smallest (most minified) code, and returns it.

Beautification engines

uglify — Mihai Bazon's amazing UglifyJS2.
js-beautify — Einar Lielmanis' js-beautify.

API

If you'd like to use minifyjs programmatically, you can do so by using require('minifyjs'). Currently, the API looks like this:

mjs = require('minifyjs');

//Minify some code
mjs.minify(code, options, callback);

//Beautify some code
mjs.beautify(code, options, callback);

Where

code is a stream.Readable containing the code to be processed.
options is a key/value hash. Options include: engine (the engine to use), level (Level of minification. The lower, the less minified).
callback is a Function to be called once the code is returned from the engine. It's passed back in the format callback(error, code);

Node that a callback is required because some methods (read: gcc) require asynchronous calls. In order to support this sort of engine, all code comes from callbacks. A good example may be:

var myCode = "...codehere...";
function presentCode(error, code) {
    if (error) {
        throw error;
    }
    //Present the code to the user...
}
require('minifyjs').minify(myCode, { engine: 'yui' }, presentCode);

Conclusion

Enjoy! Please fork, push and file issues as desired. Feel free to contribute!

License

MinifyJS is released under the MIT License.