added scalafix and scalafmt

.scalafix.conf

@@ -0,0 +1,25 @@
+rules = [
+  RemoveUnused
+  DisableSyntax
+  LeakingImplicitClassVal
+  NoValInForComprehension
+  ProcedureSyntax
+]
+
+DisableSyntax.noVars = true
+DisableSyntax.noThrows = true
+DisableSyntax.noNulls = true
+DisableSyntax.noReturns = true
+DisableSyntax.noAsInstanceOf = false
+DisableSyntax.noIsInstanceOf = true
+DisableSyntax.noXml = true
+DisableSyntax.noFinalVal = true
+DisableSyntax.noFinalize = true
+DisableSyntax.noValPatterns = true
+DisableSyntax.regex = [
+  {
+    id = noJodaTime
+    pattern = "org\\.joda\\.time"
+    message = "Use java.time instead"
+  }
+]

.scalafmt.conf

@@ -0,0 +1,10 @@
+version = 2.4.2
+project.git = true
+maxColumn = 120
+align = more
+assumeStandardLibraryStripMargin = true
+rewrite.rules = [AvoidInfix, SortImports, RedundantBraces, RedundantParens, SortModifiers]
+rewrite.redundantBraces.stringInterpolation = true
+spaces.afterTripleEquals = true
+continuationIndent.defnSite = 2
+includeCurlyBraceInSelectChains = false

build.sbt

@@ -31,8 +31,11 @@ lazy val sharedSettings = Seq(
     "-deprecation",
     "-feature",
     "-language:higherKinds",
-    "-Ymacro-annotations"
-  )
+    "-Ymacro-annotations",
+    "-Ywarn-unused:imports",
+  ),
+  semanticdbEnabled := true,
+  semanticdbVersion := scalafixSemanticdb.revision,
 )
 
 lazy val jsSettings = Seq(

js/src/main/scala/example/modules/Chat.scala

@@ -20,6 +20,7 @@ import slinky.web.html._
     val (errors, setErrors) = useState(Vector[String]())
     val (msgs, setMsgs) = useState(Vector[String]())
     val (autoscroll, setAutoscroll) = useState(true)
+
     val chatRef = React.createRef[html.Div]
 
     def handleUsername(e: SyntheticEvent[html.Input, Event]): Unit = setUsername(e.target.value)

project/plugins.sbt

@@ -4,3 +4,5 @@ addSbtPlugin("ch.epfl.scala" % "sbt-scalajs-bundler" % "0.17.0")
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.7.0")
 addSbtPlugin("io.spray" % "sbt-revolver" % "0.9.1")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.15")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.3.4")