akiomik / sbt-uglify-es

An sbt-web plugin to perform uglify-es optimization



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


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

resolvers += Resolver.url("sbt Plugin Repository", url("https://dl.bintray.com/akiomik/sbt-plugins/"))(Resolver.ivyStylePatterns)

addSbtPlugin("com.github.akiomik" % "sbt-uglify-es" % "1.0.0")

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.


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

includeFilter in uglify := 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.


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


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 uglify-es documentation for details on the options):

Option Description Default
uglifyBeautify Enables beautify. false
uglifyBeautifyOptions Options for beautify such as beautify, preamble etc. Nil
uglifyComments Specifies comments handling. None
uglifyCompress Enables compression. Set true to compress. true
uglifyCompressOptions A sequence of options for compression such as pure_funcs etc. Nil
uglifyConfigFile Read minify() options from JSON file. None
uglifyDefine Define globals. None
uglifyEcma Specifies ECMAScript release. None
uglifyIe8 Supports non-standard Internet Explorer 8. false
uglifyKeepClassnames Does not mangle/drop class names. false
uglifyKeepFnames Does not mangle/drop function names. false
uglifyMangle Enables name mangling. true
uglifyMangleOptions Options for mangling such as builtins, debug etc. Nil
uglifyNameCache Specifies a file to hold mangled name mappings. None
uglifyParse Specifies parser options such as acorn, bare_returns etc. Nil
uglifySafari10 Supports non-standard Safari 10/11. false
uglifySelf Builds UglifyJS as a library. false
uglifyTimings Displays operations run time on STDERR. false
uglifyToplevel Compresses and/or mangles variables in top level scope. false
uglifyVerbose Prints diagnostic messages. false
uglifyWarn Prints warning messages. false
uglifyWrap Embed everything in a big function. None
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.


sbt '^ scripted'

© Typesafe Inc., 2014 © Akiomi KAMAKURA, 2018