sbt-uglify

An sbt-web plugin to perform UglifyJS optimization on the asset pipeline.

Usage

To use this plugin, use the addSbtPlugin command within your project's project/plugins.sbt file:

addSbtPlugin("com.github.sbt" % "sbt-uglify" % "3.0.0")

Your project's build file also needs to enable sbt-web plugins. For example, with build.sbt:

lazy val root = (project in file(".")).enablePlugins(SbtWeb)

As with all sbt-web asset pipeline plugins you must declare their order of execution:

pipelineStages := Seq(uglify)

A standard build profile for the Uglify optimizer is provided which will mangle variables for obfuscation and compression. Each input .js file found in your assets folders will have a corresponding .min.js file and source maps will also be generated.

includeFilter

If you wish to limit or extend what is uglified then you can use filters:

uglify / includeFilter := GlobFilter("myjs/*.js"),

...where the above will include only those files under the myjs folder.

The sbt excludeFilter is also available to the uglify scope and defaults to excluding the public folder and extracted Webjars.

uglifyOps

If you wish to change how files are mapped from input to output, you can change the uglifyOps setting to point at another grouping.

The default ops takes a source file and produces minified file and source map:

uglifyOps := UglifyOps.singleFileWithSourceMapOut

This ops takes a source file and produces minified file only (no source map):

uglifyOps := UglifyOps.singleFile

This ops takes a source file and source map and produces minified file and combined source map. Your includeFilter must include source map files for this to work:

uglifyOps := UglifyOps.singleFileWithSourceMapInAndOut

Settings

You are able to use and/or customize settings already made, and add your own. Here are a list of relevant settings and their meanings (please refer to the UglifyJS documentation for details on the options):

Option	Description	Default
uglifyComments	Specifies comments handling.	None
uglifyCompress	Enables compression. Set true to compress.	true
uglifyCompressOptions	A sequence of options for compression such as hoist_vars, if_return etc.	Nil
uglifyDefine	Define globals.	None
uglifyEnclose	Enclose in one big function.	false
uglifyIncludeSource	Include the content of source files in the source map as the sourcesContent property.	false
uglifyMangle	Enables name mangling.	true
uglifyMangleOptions	Options for mangling such as sort, topLevel etc.	Nil
uglifyPreamble	Any preamble to include at the start of the output.	None
uglifyReserved	Reserved names to exclude from mangling.	Nil
uglifyOps	A function defining how to combine input files into output files.	UglifyOps.singleFileWithSourceMapOut

The plugin is built on top of JavaScript Engine which supports different JavaScript runtimes.