How to get Alternate Layout Name to delete alternate layout

Something like the following should work. I have not worked with alternatelayouts so there maybe a more elegant way, suggestions are always welcome for improvement

var altLayout = app.documents[0].pages.everyItem().appliedAlternateLayout
var uniqueList = {}
while(a = altLayout.pop())
     uniqueList[a.alternateLayout] = true
for(var a in uniqueList)
     alert(a)

-Manan