       attribute: splitOp.attribute
       operation: 'filter'
       type: 'within'
-      value: value.map((time) -> time.toISOString())
+      value: value.map((time) -> if time instanceof Date then time.toISOString() else time)
     }
   else
     newFilterPiece = {

      return driver async, callback

    root = getKnownTree(condensedQuery)
    console.log JSON.stringify(root, null, 2)
    unknownQuery = getUnknownQuery(query, root, condensedQuery)
    console.log JSON.stringify(unknownQuery, null, 2)
    if not unknownQuery?
      callback(null, root)
      return


    bucketFilter = splitOp.bucketFilter
    if bucketFilter?
      if upperSplitValue not in bucketFilter.values
        return {
          prop
