Database
[{"id":1234,"products":[{"productId":111,"path":"H"},{"productId":112,"path":"H"},{"productId":113,"path":"P"}]},{"id":1235,"products":[{"productId":111,"path":"H"},{"productId":112,"path":"H"},{"productId":113,"path":"P"}]}]
Query
db.collection.aggregate([{"$project":{"firstFiveProducts":{"$firstN":{"n":2,"input":"$products"}}}}])