A Grunt plugin for compressing files using Zopfli.

This plugin requires Grunt v0.4.0+. Also, Zopfli must be installed.

Installing Zopfli is easy with Homebrew — just run the following command:

brew update; brew install zopfli

If you’re not using Homebrew, get Zopfli’s source code, compile the zopfli binary, and move it to any directory in our $PATH. Assuming /usr/local/bin is in your $PATH, you can just follow these steps:

cd /tmp
curl -O https://zopfli.googlecode.com/files/zopfli-1.0.0.zip
unzip zopfli-1.0.0.zip
cd zopfli-1.0.0
make
chmod +x zopfli
cp zopfli /usr/local/bin

Here’s an equivalent oneliner that can safely be copy-pasted:

cd /tmp; curl -O "https://zopfli.googlecode.com/files/zopfli-1.0.0.zip"; unzip zopfli-1.0.0.zip; cd zopfli-1.0.0; make; chmod +x zopfli; cp zopfli /usr/local/bin

If you haven’t used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you’re familiar with that process, you may install this plugin with this command:

npm install grunt-zopfli --save-dev

One the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-zopfli');

In your project’s Gruntfile, add a section named zopfli to the data object passed into grunt.initConfig().

grunt.initConfig({
	'zopfli': {
		'options': {
			// Task-specific options go here
		},
		'your-target': {
			'options': {
				// Target-specific options go here
			},
			'files': {
				// Target-specific file lists go here
			},
			'path': '' // Optional full path to `zopfli` binary; defaults to `zopfli` in `$PATH`
		}
	}
});

Note: Grunt offers several ways to define src → dest (source → destination) file mappings. This plugin supports all of them.

The options property can be used to override the following settings:

Type: Boolean Default: true

Show the original and compressed file size (true). Or not (false). Whatever.

Type: Number Default: 15

The number of iterations Zopfli will perform. Higher values result in better compression at the cost of speed.

Type: String Possible values: 'gzip', 'zlib', 'deflate' Default: 'gzip'

The desired output format.

Type: Boolean Default: false

By default (false), Zopfli will perform block splitting first instead of last. Set to true to make Zopfli perform block splitting last instead of first.

Here’s a practical example of grunt-zopfli with default settings:

grunt.initConfig({
	'zopfli': {
		'compress-plugins': {
			'files': {
				'dist/plugins.min.js.gz': 'dist/plugins.min.js'
			}
		}
	}
});

Here’s a slightly more advanced example:

grunt.initConfig({
	'zopfli': {
		'compress-plugins': {
			'options': {
				'report': false, // don’t show original and compressed size (default: `true`)
				'iterations': 50, // min value: `1`; (undocumented) max value: `99999999999` (default: `15`)
				'format': 'zlib', // `'gzip'`, `'zlib'`, `'deflate'` (default: `'gzip'`)
				'splitLast': true // perform block splitting first instead of last (default: `false`)
			},
			'files': {
				'dist/plugins.min.js.gz': 'dist/plugins.min.js'
			}
		}
	}
});

Or, to compress all files in input-directory, and save the compressed files to output-directory, using Grunt’s dynamic path expansion:

grunt.initConfig({
	'zopfli': {
		'compress': {
			'options': {
				'iterations': 20 // min value: `1`; (undocumented) max value: `99999999999` (default: `15`)
			},
			'files': {
				'src': ['input-directory/*'],
				'dest': 'output-directory/',
				'expand': true,
				'ext': '.js.gz'
			}
		}
	}
});

Mathias Bynens

grunt-zopfli is dual licensed under the MIT and GPL licenses.