[{item:"journal",instock:[{warehouse:"A",qty:5},{warehouse:"C",qty:15,type:["hello","world","wassup","yo"]}]},{item:"notebook",instock:[{warehouse:"C",qty:5}]},{item:"paper",instock:[{warehouse:"A",qty:60},{warehouse:"B",qty:1515,type:["hello","wassup","yo"]}]},{item:"planner",instock:[{warehouse:"A",qty:40},{warehouse:"B",qty:515,type:["hello"]}]},{item:"postcard",instock:[{warehouse:"B",qty:15},{warehouse:"C",qty:3515,type:["wassup","yo"]}]}]

db.collection.find({"instock.type":"hello"})