Minify files with UglifyJS.
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');
Run this task with the grunt uglify
command.
Task targets, files and options may be specified according to the grunt Configuring tasks guide.
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.
sourceMappingURL
- This is calculated automatically now
sourceMapPrefix
- No longer necessary for the above reason
sourceMap
- Only accepts a Boolean
value. Generates a map with a default name for you
sourceMapRoot
- The location of your sources is now calculated for you when sourceMap
is set to true
but you can set manual source root if needed
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
expression
- Accepts a Boolean
value. Parse a single expression (JSON or single functions)
sourceMappingURLBase
- Use this to prefix the automatically calculated sourceMappingURL
quoteStyle
- Accepts integers 0
(default), 1
, 2
, 3
. Enforce or preserve quotation mark style.
This task primarily delegates to UglifyJS2, so please consider the UglifyJS documentation as required reading for advanced configuration.
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). View all options here.
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()
. View all options here.
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()
. View all options here
Type: Boolean
Default: false
Parse a single expression, rather than a program (for parsing JSON)
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.
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.
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.
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.
Type: Boolean
Default: false
Pass this flag if you want to include the content of source files in the source map as sourcesContent property.
Type: String
Default: undefined
With this option you can customize root URL that browser will use when looking for sources.
If the sources are not absolute URLs after prepending of the sourceMapRoot
, the sources are resolved relative to the source map.
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.
Type: String
Default: undefined
When used, this option will add a base URL to the source maps filename. If undefined
the relative path will be used.
Example: //# sourceMappingURL=[baseURL][sourceMapFilename]
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.
Type: Number
Default: 32000
Limit the line length in symbols. Pass maxLineLen = 0 to disable this safety feature.
Type: Boolean
Default: false
Enables to encode non-ASCII characters as \uXXXX.
Type: Boolean
Default: false
When using wrap
this will make all global functions and variables available via the export variable.
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 eithertrue
orfalse
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.
Type: Boolean
Default: false
Pass this flag if you don't care about full compliance with Internet Explorer 6-8 quirks.
Type: Boolean
Default: false
Use this flag to turn on object property name mangling.
Type: Boolean
Default: false
Use this flag in conjunction with mangleProperties
to prevent built-in browser object properties from being mangled.
Type: Array
Default: []
Use this with mangleProperties
to pass one or more JSON files containing a list of variables and object properties
that should not be mangled. See the UglifyJS docs for more info on the file syntax.
Type: String
Default: empty string
A string that is a path to a JSON cache file that uglify will create and use to coordinate symbol mangling between
multiple runs of uglify. Note: this generated file uses the same JSON format as the exceptionsFiles
files.
Type: Integer
Default: 0
Preserve or enforce quotation mark style.
0
will use single or double quotes such as to minimize the number of bytes (prefers double quotes when both will do)1
will always use single quotes2
will always use double quotes3
will preserve original quotation marks
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']
}
}
}
});
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']
}
}
}
});
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']
}
}
}
});
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']
}
}
}
});
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.
Specify drop_console: true
as part of the compress
options to discard calls to console.*
functions.
This will supress warning messages in the console.
// Project configuration.
grunt.initConfig({
uglify: {
options: {
compress: {
drop_console: true
}
},
my_target: {
files: {
'dest/output.min.js': ['src/input.js']
}
}
}
});
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']
}
}
}
});
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']
}
}
}
});
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'
}]
}
}
});
This configuration will turn on object property name mangling, but not mangle built-in browser object properties.
Additionally, variables and object properties listed in the myExceptionsFile.json
will be mangled. For more info,
on the format of the exception file format please see the UglifyJS docs.
// Project configuration.
grunt.initConfig({
uglify: {
options: {
mangleProperties: true,
reserveDOMCache: true,
exceptionsFiles: [ 'myExceptionsFile.json' ]
},
my_target: {
files: {
'dest/output.min.js': ['src/input.js']
}
}
}
});
Turn on use of name mangling cache to coordinate mangled symbols between outputted uglify files. uglify will the
generate a JSON cache file with the name provided in the options. Note: this generated file uses the same JSON format
as the exceptionsFiles
files.
// Project configuration.
grunt.initConfig({
uglify: {
options: {
nameCache: '.tmp/grunt-uglify-cache.json',
},
my_target: {
files: {
'dest/output1.min.js': ['src/input1.js'],
'dest/output2.min.js': ['src/input2.js']
}
}
}
});
- 2015-04-07 v0.9.0 added hook into uglify's mangling functionality
- 2015-03-30 v0.8.1 lock uglify to 2.4.17 due to breaking changes
- 2015-02-19 v0.8.0 Add
screwIE8
option. Fix issue with explicitcompress
in node 0.12.0. - 2014-12-23 v0.7.0 Adds sourceMapRoot options. Updates readme descriptions. Removes reference to cleancss.
- 2014-09-17 v0.6.0 Output fixes. ASCIIOnly option. Other fixes.
- 2014-07-25 v0.5.1 Chalk updates. Output updates.
- 2014-03-01 v0.4.0 remove grunt-lib-contrib dependency and add more colors
- 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 Tue Apr 07 2015 21:04:14.