Update to scalajs 1.0.1 (#454)

build.sbt

@@ -40,13 +40,14 @@ def jsonDependencies(scalaVersion: String) = Seq(
 
 // Common settings
 
-def playJsonMimaSettings =
-  Seq(
-    mimaPreviousArtifacts := Set(
-      (organization.value %%% moduleName.value % previousStableVersion.value
-        .getOrElse(throw new Error("Unable to determine previous version")))
-    )
-  )
+// Do not check for previous JS artifacts for upgrade to Scala.js 1.0 because no sjs1 artifacts exist
+def playJsonMimaSettings = Seq(
+  mimaPreviousArtifacts := ((crossProjectPlatform.?.value, previousStableVersion.value) match {
+    case (Some(JSPlatform), Some("2.8.1")) => Set.empty
+    case (_, Some(previousVersion))        => Set(organization.value %%% moduleName.value % previousVersion)
+    case _                                 => throw new Error("Unable to determine previous version")
+  })
+)
 
 // Workaround for https://github.com/scala-js/scala-js/issues/2378
 // Use "sbt -DscalaJSStage=full" in .travis.yml

project/plugins.sbt

@@ -15,7 +15,7 @@ addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.7.0")
 
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.6.0")
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.33")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.0.1")
 
 addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.0.0")