[{_id:"Toy",name:"Toyname",child:[{item:"Toy1",isActive:"1",Type:"New"},{item:"Toy2",isActive:"2",Type:"Old"},{item:"Toy3",isActive:"1",Type:"New"}]}]

db.collection.aggregate([{"$match":{"_id":"Toy"}},{"$unwind":"$child"},{"$match":{"child.isActive":"1"}},{"$group":{"_id":"$_id","name":{"$first":"$name"},"child":{"$push":"$child"}}}])