grunt-contrib-uglify

Minify files with UglifyJS.

npm install grunt-contrib-uglify
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grunt-contrib-uglify v0.4.0 Build Status

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.

Migrating from 2.x to 3.x

Version 3.x introduced changes to configuring source maps. Accordingly, if you don't use the source map options you should be able to upgrade seamlessly. If you do use source maps, see below.

Removed options

sourceMapRoot - The location of your sources is now calculated for you when sourceMap is set to true
sourceMapPrefix - No longer necessary for the above reason
sourceMappingURL - Once again, this is calculated automatically

Changed options

sourceMap - Only accepts a Boolean value. Generates a map with a default name for you

New options

sourceMapName - Accepts a string or function to change the location or name of your map sourceMapIncludeSources - Embed the content of your source files directly into the map

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: 'min', 'gzip'
Default: 'min'

Either report only minification result or report minification and gzip results. This is useful to see exactly how well clean-css is performing but using 'gzip' will make the task take 5-10x longer to complete. Example output.

sourceMap

Type: Boolean
Default: false

If true, a source map file will be generated in the same directory as the dest file. By default it will have the same basename as the dest file, but with a .map extension.

sourceMapName

Type: String Function
Default: undefined

To customize the name or location of the generated source map, pass a string to indicate where to write the source map to. If a function is provided, the uglify destination is passed as the argument and the return value will be used as the file name.

sourceMapIn

Type: String Function
Default: undefined

The location of an input source map from an earlier compilation, e.g. from CoffeeScript. If a function is provided, the uglify source is passed as the argument and the return value will be used as the sourceMap name. This only makes sense when there's one source file.

sourceMapIncludeSources

Type: Boolean Default: false

Pass this flag if you want to include the content of source files in the source map as sourcesContent property.

enclose

Type: Object
Default: undefined

Wrap all of the code in a closure with a configurable arguments/parameters list. Each key-value pair in the enclose object is effectively an argument-parameter pair.

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

Type: String
Default: empty string

This string will be prepended to the minified output. Template strings (e.g. <%= config.value %> will be expanded automatically.

Type: String
Default: empty string

This string will be appended to the minified output. Template strings (e.g. <%= config.value %> will be expanded automatically.

Usage examples

Basic compression

This configuration will compress and mangle 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

Generate a source map by setting the sourceMap option to true. The generated source map will be in the same directory as the destination file. Its name will be the basename of the destination file with a .map extension. Override these defaults with the sourceMapName attribute.

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

Advanced source maps

Set the sourceMapIncludeSources option to true to embed your sources directly into the map. To include a source map from a previous compilation pass it as the value of the sourceMapIn option.

// Project configuration.
grunt.initConfig({
  uglify: {
    my_target: {
      options: {
        sourceMap: true,
        sourceMapIncludeSources: true,
        sourceMapIn: 'example/coffeescript-sourcemap.js', // input sourcemap from a previous compilation
      },
      files: {
        'dest/output.min.js': ['src/input.js'],
      },
    },
  },
});

Refer to the UglifyJS SourceMap Documentation for more information.

Discard console.* functions

Specify drop_console: true as part of the compress options to discard calls to console.* functions.

// Project configuration.
grunt.initConfig({
  uglify: {
    options: {
      compress: {
        drop_console: true
      }
    },
    my_target: {
      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']
      }
    }
  }
});

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']
      }
    }
  }
});

Compiling all files in a folder dynamically

This configuration will compress and mangle the files dynamically.

// Project configuration.
grunt.initConfig({
  uglify: {
    my_target: {
      files: [{
          expand: true,
          cwd: 'src/js',
          src: '**/*.js',
          dest: 'dest/js'
      }]
    }
  }
});

Release History

  • 2014-02-27   v0.3.3   remove unnecessary calls to grunt.template.process
  • 2014-01-22   v0.3.2   fix handling of sourceMapIncludeSources option.
  • 2014-01-20   v0.3.1   fix relative path issue in sourcemaps
  • 2014-01-16   v0.3.0   refactor sourcemap support
  • 2013-11-09   v0.2.7   prepending banner if sourceMap option not set, addresses
  • 2013-11-08   v0.2.6   merged 45, 53, 85 (105 by way of duping 53) Added support for banners in uglified files with sourcemaps Updated docs
  • 2013-10-28   v0.2.5   Added warning for banners when using sourcemaps
  • 2013-09-02   v0.2.4   updated sourcemap format via /83
  • 2013-06-10   v0.2.3   added footer option
  • 2013-05-31   v0.2.2   Reverted /56 due to /58 until chrome/239660 firefox/870361 drop
  • 2013-05-22   v0.2.1   Bumped uglify to ~2.3.5 /55 /40 Changed sourcemappingUrl syntax /56 Disabled sorting of names for consistent mangling /44 Updated docs for sourceMapRoot /47 /25
  • 2013-03-14   v0.2.0   No longer report gzip results by default. Support report option.
  • 2013-01-30   v0.1.2   Added better error reporting Support for dynamic names of multiple sourcemaps
  • 2013-02-15   v0.1.1   First official release for Grunt 0.4.0.
  • 2013-01-18   v0.1.1rc6   Updating grunt/gruntplugin dependencies to rc6. Changing in-development grunt/gruntplugin dependency versions from tilde version ranges to specific versions.
  • 2013-01-09   v0.1.1rc5   Updating to work with grunt v0.4.0rc5. Switching back to this.files api.
  • 2012-11-28   v0.1.0   Work in progress, not yet officially released.

Task submitted by "Cowboy" Ben Alman

This file was generated on Sat Mar 01 2014 20:36:24.

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