Create new layer after active layer

Question

Using scriptlistener I can create a new layer called "newlayer" after the active layer. So far so good.
  var id197 = charIDToTypeID( "Mk  " );
  var desc49 = new ActionDescriptor();
  var id198 = charIDToTypeID( "null" );
  var ref41 = new ActionReference();
  var id199 = charIDToTypeID( "Lyr " );
  ref41.putClass( id199 );
  desc49.putReference( id198, ref41 );
  var id200 = charIDToTypeID( "Usng" );
  var desc50 = new ActionDescriptor();
  var id201 = charIDToTypeID( "Nm  " );
  desc50.putString( id201, "newlayer" );
  var id202 = charIDToTypeID( "Lyr " );
  desc49.putObject( id200, id202, desc50 );
  executeAction( id197, desc49, DialogModes.NO );
However, without the script listener we have
  var layerRef = app.activeDocument.artLayers.add()
  layerRef.name = newlayername
  layerRef.blendMode = BlendMode.NORMAL
  // Move the new layer after the current layer
  layerRef.moveAfter(app.activeDocument.artLayers[layerIndex])
The moveAfter command needs an index, which would mean looping though all the layers till to find the active layer (since we can't access that throughthe DOM). This seems a bit long winded to me. Or am I missing a trick here?

Answer 1

Well I would just use the scriptlistener code but if you don't want to for some reason you should make a reference to the activeLayer before add the new layer. Then use that reference as the moveAfter argument. The moveAfter method needs a layer object not a layer index. You need the index only because you are trying to supply that layer object by index.
layerRef.moveAfter(someLayerRef);
Also ( not that it really matters ) when scripting was first added there were several methods for moving a layer, moveAfter() was one of those. Those methods were combined into one method and the old methods are no longer documented in the javascript reference. So below is the documented way to move the layer.
layerRef.move(someLayerRef, ElementPlacement.PLACEAFTER);