Ported over code form pretty-differ-2 branch, tests passed.

Author: cheeseng

project/GenScalacticJS.scala

@@ -82,8 +82,8 @@ object GenScalacticJS {
   def genScala(targetDir: File, version: String, scalaVersion: String): Seq[File] =
     copyDir("scalactic/src/main/scala/org/scalactic", "org/scalactic", targetDir, List.empty) ++
     copyDir("scalactic/src/main/scala/org/scalactic/exceptions", "org/scalactic/exceptions", targetDir, List.empty) ++
-    copyDir("scalactic/src/main/scala/org/scalactic/source", "org/scalactic/source", targetDir, List.empty) ++
-    copyDir("scalactic/src/main/scala/org/scalactic/anyvals", "org/scalactic/anyvals", targetDir, List.empty) ++ 
+    copyDir("scalactic/src/main/scala/org/scalactic/source", "org/scalactic/source", targetDir, List("ObjectMeta.scala")) ++
+    copyDir("scalactic/src/main/scala/org/scalactic/anyvals", "org/scalactic/anyvals", targetDir, List.empty) ++
     GenVersions.genScalacticVersions(new File(targetDir, "org/scalactic"), version, scalaVersion)
 
   def genMacroScala(targetDir: File, version: String, scalaVersion: String): Seq[File] =

scalactic-test/src/test/scala/org/scalactic/DifferSpec.scala

@@ -65,7 +65,8 @@ class PrettifierSpec extends FunSpec with Matchers {
               case _ => Prettifier.default(o)
             }
         }
-      myLittlePretty(Yell("I like fruit loops"), Yell("I like raisin bran")) shouldBe PrettyPair("I LIKE FRUIT LOOPS!!!", "I LIKE RAISIN BRAN!!!", None)
+      val left = Yell("I like fruit loops")
+      myLittlePretty(left, Yell("I like raisin bran")) shouldBe PrettyPair("I LIKE FRUIT LOOPS!!!", "I LIKE RAISIN BRAN!!!", Some(Differ.simpleClassName(left) + "(secret: \"I like [fruit loops]\" -> \"I like [raisin bran]\")"))
     }
   }
 

scalactic-test/src/test/scala/org/scalactic/PrettifierSpec.scala

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2001-2016 Artima, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.scalactic.source
+
+trait ObjectMeta {
+
+  def fieldNames: scala.collection.immutable.IndexedSeq[String]
+
+  def hasField(name: String): Boolean = fieldNames.contains(name)
+
+  def value(name: String): Any
+
+  def typeName(name: String): String
+
+  def shortTypeName(name: String): String
+
+}
+
+object ObjectMeta {
+
+  def apply(v: Any): ObjectMeta = {
+
+    def filterDollarNumberAtTheEnd(value: String): String = {
+      val lastIdxOfDollar = value.lastIndexOf('$')
+      if (lastIdxOfDollar > 0) {
+        val afterDollar = value.substring(lastIdxOfDollar + 1)
+        try {
+          afterDollar.toInt
+          value.substring(0, lastIdxOfDollar)
+        }
+        catch {
+          case t: Throwable => value
+        }
+      }
+      else
+        value
+    }
+
+    val dict = v.asInstanceOf[scala.scalajs.js.Dictionary[Any]].flatMap { case (key, value) =>
+      val decodedKey =
+        scala.reflect.NameTransformer.decode(key).
+          replaceAllLiterally("$$und", "_").
+          replaceAllLiterally("$mcI", "").
+          replaceAllLiterally("$sp", "").
+          replaceAllLiterally("$f", "")
+
+      Some((filterDollarNumberAtTheEnd(decodedKey), value))
+    }
+
+    new ObjectMeta {
+
+      lazy val fieldNames = dict.keys.toVector.filter(_ != "$$outer")
+
+      def value(name: String): Any = {
+        dict.get(name) match {
+          case Some(value) => value
+          case None => throw new IllegalArgumentException("'" + name + "' is not attribute for this instance.")
+        }
+      }
+
+      def typeName(name: String): String = {
+        dict.get(name) match {
+          case Some(value) => value.getClass.getName
+          case None => throw new IllegalArgumentException("'" + name + "' is not attribute for this instance.")
+        }
+      }
+
+      def shortTypeName(name: String): String = {
+        dict.get(name) match {
+          case Some(value) => value.getClass.getSimpleName
+          case None => throw new IllegalArgumentException("'" + name + "' is not attribute for this instance.")
+        }
+      }
+    }
+  }
+
+}