consolidate skip 210 doc settings

build.sbt

@@ -82,7 +82,7 @@ lazy val commonJvmSettings = Seq(
 // JVM settings. https://github.com/tkawachi/sbt-doctest/issues/52
 ) ++ catsDoctestSettings
 
-lazy val catsSettings = buildSettings ++ commonSettings ++ publishSettings ++ scoverageSettings ++ skip210DocSettings
+lazy val catsSettings = buildSettings ++ commonSettings ++ publishSettings ++ scoverageSettings ++ javadocSettings
 
 lazy val scalacheckVersion = "1.12.5"
 
@@ -95,29 +95,27 @@ lazy val testingDependencies = Seq(
   libraryDependencies += "org.typelevel" %%% "catalysts-macros" % "0.0.2" % "test",
   libraryDependencies += "org.scalatest" %%% "scalatest" % "3.0.0-M7" % "test")
 
+
 /**
- * Remove 2.10 projects from doc generation, as the macros used in the projects
- * cause problems generating the documentation on scala 2.10. As the APIs for 2.10
- * and 2.11 are the same this has no effect on the resultant documentation, though
- * it does mean that the scaladocs cannot be generated when the build is in 2.10 mode.
- */
-def noDocProjects(sv: String): Seq[ProjectReference] = CrossVersion.partialVersion(sv) match {
-    case Some((2, 10)) => Seq[ProjectReference](coreJVM)
-    case _ => Nil
+  * Remove 2.10 projects from doc generation, as the macros used in the projects
+  * cause problems generating the documentation on scala 2.10. As the APIs for 2.10
+  * and 2.11 are the same this has no effect on the resultant documentation, though
+  * it does mean that the scaladocs cannot be generated when the build is in 2.10 mode.
+  */
+def docsSourcesAndProjects(sv: String): (Boolean, Seq[ProjectReference]) =
+  CrossVersion.partialVersion(sv) match {
+    case Some((2, 10)) => (false, Nil)
+    case _ => (true, Seq(coreJVM, freeJVM))
   }
 
-lazy val skip210DocSettings = Seq(
-  sources in (Compile, doc) := (
-    CrossVersion.partialVersion(scalaVersion.value) match {
-      case Some((2, 10)) => Nil
-      case _ => (sources in (Compile, doc)).value
-    })
+lazy val javadocSettings = Seq(
+  sources in (Compile, doc) := (if (docsSourcesAndProjects(scalaVersion.value)._1) (sources in (Compile, doc)).value else Nil)
 )
 
 lazy val docSettings = Seq(
   autoAPIMappings := true,
   unidocProjectFilter in (ScalaUnidoc, unidoc) :=
-    inProjects(coreJVM, freeJVM) -- inProjects(noDocProjects(scalaVersion.value): _*),
+    inProjects(docsSourcesAndProjects(scalaVersion.value)._2:_*),
   site.addMappingsToSiteDir(mappings in (ScalaUnidoc, packageDoc), "api"),
   site.addMappingsToSiteDir(tut, "_tut"),
   ghpagesNoJekyll := false,