There are pieces of scala code that explain Scala syntax and related things - like what you can do with all this
Sometimes we have to read some articles, forums, blogs to understand the thing.
But if we want just remind ourselves something we already knew, then is better just look at code sample. You could easily change it and play with it and see what's going on.
In this case "the thing" is:
Scala Language (lang folder) and its satellites technologies, such as ScalaJS, Apache Spark, Akka and more.
There are samples of these in form of code that explains how to use it all.
This code is supposed to be isolated as much as possible - like if we wish to explain/remember one feature of Scala then we are not going to use 5 more extra features for that (which might not be gotten yet by a reader of this code).
Each example has no more than 100 lines of code. Also there is tagging is used in order to show to the reader what feature is involved for particular example. Like #feature-1 #feature-3.
sbt & nodejs (to work with ScalaJS samples) should be installed
NOTE: as SBT project, the project/Build.scala defines the dependencies and sub-projects. So, to build run a particular project, say ScalaJS:
Switch to that project, for example: