Fix #9: selection.data key with simple function

- allow use of a simple function with function only for origin type Datum

Author: spaced

src/main/scala/org/singlespaced/d3js/selection.scala

@@ -69,8 +69,10 @@ trait BaseSelection[Datum, T <: BaseSelection[Datum,T]] extends BaseDom[Datum,T]
   def data(): js.Array[Datum] = js.native
   def data[NewDatum](data: js.Array[NewDatum]): Update[NewDatum] = js.native
   def data[NewDatum](data: js.Array[NewDatum], key: js.ThisFunction2[Datum|NewDatum,js.UndefOr[NewDatum], Int, String]): Update[NewDatum] = js.native
+  def data[NewDatum <: Datum](data: js.Array[NewDatum], key: js.Function2[Datum, Int, String]): Update[NewDatum] = js.native
   def data[NewDatum](data: DatumFunction[js.Array[NewDatum]], key: js.ThisFunction2[Datum|NewDatum,js.UndefOr[NewDatum], Int, String]): Update[NewDatum] = js.native
 
+
   def filter(selector: DatumFunction[Boolean]): T = js.native
 
   def datum(): Datum = js.native

src/test/scala/org/singlespaced/d3js/SelectionTest.scala

@@ -3,7 +3,8 @@ package org.singlespaced.d3js
 import org.scalajs.dom
 import utest._
 import scala.scalajs.js
-import scala.scalajs.js.{ThisFunction, |}
+import scala.scalajs.js.`|`
+import org.singlespaced.d3js.Ops._
 object SelectionTest extends TestSuite {
 
 
@@ -30,6 +31,16 @@ object SelectionTest extends TestSuite {
       }
       sel.data[Int](js.Array(5),function).enter().append("p")
     }
+    'd3_dataWithKey_simpleFunction {
+      //arrange
+      class MyData(val id:String)
+      class MySubData(id:String) extends MyData(id)
+      val sel=d3.selectAll("p").data(js.Array(new MyData("1")))
+      val function= (d:MyData) => d.id
+      //act
+      sel.data[MySubData](js.Array(new MySubData("2")),function).enter().append("p")
+      //assert
+    }
 
 
   }