Speed up Javascript uglification in Play 2.3.x build for external Webjar sources

3
votes

I'm using Play framework 2.3.6 and Webjars for web lib dependencies. That is, my build.sbt contains something like "org.webjars" % "angularjs" % "1.2.26". To uglify my Javascript sources I added pipelineStages := Seq(rjs, uglify, digest, gzip) to my build.sbt.

Now, when running Play's 'stage' or 'dist' tasks it looks like all Javascript files getting uglified, that is, also files from the Webjar libraries.
[info] Uglify2 file: /target/web/rjs/build/lib/angularjs/angular.js

I would have expected that sources from the external Webjar libraries are left untouched as there already is a minified version. One problem with that is that the uglify process takes way too long. How can I speed up the uglification process?

2
javascriptplayframeworksbtuglifyjs2webjars

2 Answers

1
votes

There are two ways to speed up the Javascript building steps:

  • Install node.js and set export SBT_OPTS="$SBT_OPTS -Dsbt.jse.engineType=Node" before running the activator. Using node.js instead of the default Javascript engine gives a very significant speedup. More details can be found here: Migration to play 2.3, see section about sbt-web

  • Customize the build steps, e.g.

    • disable minification by adding to build.sbt: RjsKey.optimize := "none"
    • limit uglification by adding to build.sbt: e.g. includeFilter in uglify := GlobFilter("myjs/*.js"),

You can find more details about the options on the github site of these plugins:

sbt-uglify

sbt-rjs

1
votes

Even though that the sbt-uglify documentation says that excludeFilter should exclude webjars and public folder, it doesn't.

Follow Martin's reponse customization part, except that he maid y typo, add an S to RjsKeys:

RjsKeys.optimize := "none"