grunt-contrib-uglify

Minify files with UglifyJS.

Getting Started

This plugin requires Grunt ~0.4.0

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-contrib-uglify --save-dev

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

grunt.loadNpmTasks('grunt-contrib-uglify');

Uglify task

Run this task with the grunt uglify command.

Task targets, files and options may be specified according to the grunt Configuring tasks guide.

Options

This task primarily delegates to UglifyJS2, so please consider the UglifyJS documentation as required reading for advanced configuration.

mangle

Type: Boolean Object Default: {}

Turn on or off mangling with default options. If an Object is specified, it is passed directly to ast.mangle_names() and ast.compute_char_frequency() (mimicking command line behavior).

compress

Type: Boolean Object Default: {}

Turn on or off source compression with default options. If an Object is specified, it is passed as options to UglifyJS.Compressor().

beautify

Type: Boolean Object Default: false

Turns on beautification of the generated source code. An Object will be merged and passed with the options sent to UglifyJS.OutputStream()

report

Choices: false 'min' 'gzip' Default: false

Either do not report anything, report only minification result, or report minification and gzip results. This is useful to see exactly how well Uglify is performing, but using 'gzip' can add 5-10x runtime task execution.

Example ouput using 'gzip':

Original: 198444 bytes.
Minified: 101615 bytes.
Gzipped:  20084 bytes.

sourceMap

Type: String Function Default: undefined

The location to output the sourcemap. If a function is provided, the uglify destination is passed as the argument and the return value will be used as the sourceMap name.

sourceMapRoot

Type: String Default: undefined

The location where your source files can be found. This option sets the root location in the sourcemap file itself.

sourceMapIn

Type: String Default: undefined

The location of an input source map from an earlier compilation, e.g. from CoffeeScript.

sourceMappingURL

Type: String Function Default: undefined

The location of your sourcemap. Defaults to the location you use for sourceMap, override if you need finer control. Provide a function to dynamically generate the sourceMappingURL based off the destination.

sourceMapPrefix

Type: Number Default: undefined

The number of directories to drop from the path prefix when declaring files in the source map.

wrap

Type: String Default: undefined

Wrap all of the code in a closure, an easy way to make sure nothing is leaking. For variables that need to be public exports and global variables are made available. The value of wrap is the global variable exports will be available as.

exportAll

Type: Boolean Default: false

When using wrap this will make all global functions and variables available via the export variable.

preserveComments

Type: Boolean String Function Default: undefined Options: false 'all' 'some'

Turn on preservation of comments.

• false will strip all comments
• 'all' will preserve all comments in code blocks that have not been squashed or dropped
• 'some' will preserve all comments that start with a bang (!) or include a closure compiler style directive (@preserve @license @cc_on)
• Function specify your own comment preservation function. You will be passed the current node and the current comment and are expected to return either true or false

banner

Type: String Default: empty string

This string will be prepended to the beginning of the minified output. It is processed using grunt.template.process, using the default options.

(Default processing options are explained in the grunt.template.process documentation)

Usage examples

Basic compression

In this example, running grunt uglify:my_target (or grunt uglify because uglify is a [multi task][]) will mangle and compress the input files using the default options.

// Project configuration.
grunt.initConfig({
  uglify: {
    my_target: {
      files: {
        'dest/output.min.js': ['src/input1.js', 'src/input2.js']
      }
    }
  }
});

No mangling

Specify mangle: false to prevent changes to your variable and function names.

// Project configuration.
grunt.initConfig({
  uglify: {
    options: {
      mangle: false
    },
    my_target: {
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Reserved identifiers

You can specify identifiers to leave untouched with an except array in the mangle options.

// Project configuration.
grunt.initConfig({
  uglify: {
    options: {
      mangle: {
        except: ['jQuery', 'Backbone']
      }
    },
    my_target: {
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Source maps

Configure basic source map output by specifying a file path for the sourceMap option.

// Project configuration.
grunt.initConfig({
  uglify: {
    my_target: {
      options: {
        sourceMap: 'path/to/source-map.js'
      },
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Advanced source maps

You can specify the parameters to pass to UglifyJS.SourceMap() which will allow you to configure advanced settings.

Refer to the UglifyJS SourceMap Documentation for more information.

// Project configuration.
grunt.initConfig({
  uglify: {
    my_target: {
      options: {
        sourceMap: 'path/to/source-map.js',
        sourceMapRoot: 'http://example.com/path/to/src/', // the location to find your original source
        sourceMapIn: 'example/coffeescript-sourcemap.js', // input sourcemap from a previous compilation
        }
      },
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Beautify

Specify beautify: true to beautify your code for debugging/troubleshooting purposes. Pass an object to manually configure any other output options passed directly to UglifyJS.OutputStream().

See UglifyJS Codegen documentation for more information.

Note that manual configuration will require you to explicitly set beautify: true if you want traditional, beautified output.

// Project configuration.
grunt.initConfig({
  uglify: {
    my_target: {
      options: {
        beautify: true
      },
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    },
    my_advanced_target: {
      options: {
        beautify: {
          width: 80,
          beautify: true
        }
      },
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Banner comments

In this example, running grunt uglify:my_target will prepend a banner created by interpolating the banner template string with the config object. Here, those properties are the values imported from the package.json file (which are available via the pkg config property) plus today's date.

Note: you don't have to use an external JSON file. It's also valid to create the pkg object inline in the config. That being said, if you already have a JSON file, you might as well reference it.

// Project configuration.
grunt.initConfig({
  pkg: grunt.file.readJSON('package.json'),
  uglify: {
    options: {
      banner: '/*! <%= pkg.name %> - v<%= pkg.version %> - ' +
        '<%= grunt.template.today("yyyy-mm-dd") %> */'
    },
    my_target: {
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Conditional compilation

You can also enable UglifyJS conditional compilation. This is commonly used to remove debug code blocks for production builds.

See UglifyJS global definitions documentation for more information.

// Project configuration.
grunt.initConfig({
  uglify: {
    options: {
      compress: {
        global_defs: {
          "DEBUG": false
        },
        dead_code: true
      }
    },
    my_target: {
      files: {
        'dest/output.min.js': ['src/input.js']
      }
    }
  }
});

Release History

• 2013-03-13   v0.2.0   No longer report gzip results by default. Support report option.
• 2013-01-29   v0.1.2   Added better error reporting Support for dynamic names of multiple sourcemaps
• 2013-02-14   v0.1.1   First official release for Grunt 0.4.0.
• 2013-01-17   v0.1.1rc6   Updating grunt/gruntplugin dependencies to rc6. Changing in-development grunt/gruntplugin dependency versions from tilde version ranges to specific versions.
• 2013-01-08   v0.1.1rc5   Updating to work with grunt v0.4.0rc5. Switching back to this.files api.
• 2012-11-27   v0.1.0   Work in progress, not yet officially released.

Task submitted by "Cowboy" Ben Alman

This file was generated on Fri Mar 15 2013 15:50:39.