db={orders:[{"_id":"wJNEiSYwBd5ozGtLX","orderId":52713,"createdAt":ISODate("2020-01-31T04:34:13.790Z"),"status":"closed","orders":[{"_id":"ziPzwLuZrz9MNkaRT","productId":10290,"quantity":2},{"_id":"ziPzwLuZrz9MNkaRY","productId":10291,"quantity":2}]}],itemTypes:[{"_id":"F8f6HBooNEs7BNLAz","typeId":21,"name":"Keychain"},{"_id":"F8f6HBooNEs7BNLAz1","typeId":22,"name":"Ball"}],brands:[{"_id":"F8f6HBooNEs7BNLAzB1","brandId":101,"name":"Adidas"},{"_id":"F8f6HBooNEs7BNLAzB2","brandId":102,"name":"Nike"}],products:[{"_id":"238cwwLkZa6gKNN86","productId":10290,"typeId":21,"brandId":101,"title":"Product Title","price":9.9},{"_id":"238cwwLkZa6gKNN87","productId":10291,"typeId":22,"brandId":102,"title":"Product Title","price":9}]}

db.orders.aggregate([{$unwind:"$orders"},{"$lookup":{"from":"products","localField":"orders.productId","foreignField":"productId","as":"products"}},{"$lookup":{"from":"itemTypes","localField":"products.typeId","foreignField":"typeId","as":"itemTypes"}},{"$lookup":{"from":"brands","localField":"products.brandId","foreignField":"brandId","as":"brands"}},{"$set":{"orders.price":{"$arrayElemAt":["$products.price",0]},"orders.typeId":{"$arrayElemAt":["$products.typeId",0]},"orders.brandId":{"$arrayElemAt":["$products.brandId",0]},"orders.typeName":{"$arrayElemAt":["$itemTypes.name",0]},"orders.brandName":{"$arrayElemAt":["$brands.name",0]}}},{$group:{_id:"$_id",createdAt:{$first:"$createdAt"},status:{$first:"$status"},orderId:{$first:"$orderId"},orders:{$push:"$orders"}}}])