Scala Shell CSS Standard ML JavaScript HTML
Latest commit 1bbafd0 Jul 12, 2018


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User documentation

Head over to the user docs for instructions on how to install scalafmt.

Quick help

  • sbt compile on a clean machine will fail to compile the scalafmt-intellij project.
    • if you plan to develop the intellij plugin, run downloadIdea first to fetch the IntelliJ SDK (~600mb).
    • or, run sbt test or sbt core/compile (specific project).
  • Run all unit tests: sbt test
  • Run only formatting tests: tests/testOnly *FormatTests.
  • Write new formatting test: read this doc.
  • Build docs: sbt readme/run will create the docs, which you can open with open readme/target/scalatex/index.html. Docs are built with Scalatex.
  • Hack on IntelliJ plugin: see this doc.
  • Hack on SBT plugin: run sbt scripted.
  • Run jmh benchmarks: ./bin/
  • Run formatter on millions of lines of code: tests/test:runMain org.scalafmt.ScalafmtProps (slow, and requires a lot of memory/cpu)
  • Debug performance: after each test run in FormatTests, a flamegraph report like this one is generated in target/index.html. I usually keep a browser tab open at localhost:3000/target/index.html along with this background process: browser-sync start --server --files "target/*.html". See Browsersync.
  • intellij/compile:compileIncremental failed? Run downloadIdea to download custom IntelliJ plugin. The download may take a while.


The current maintainers (people who can merge pull requests) are:

An up-to-date list of contributors is available here:

We strive to offer a welcoming environment to learn, teach and contribute.


JProfiler generously supports scalafmt with its full-featured Java Profiler.