Mongo convert embedded document to array

Question

Is there a way to convert a nested document structure into an array? Below is an example:

Input

\"experience\" : {
        \"0\" : {         


        

Answer 1

For mongoDB version >4.2 :

db.doc.aggregate([{ $match: {'experience.0': { $exists: false } } },
    {$project:{experience:["$experience.0"]}}, { $merge: { into: "doc", on: "_id" }
])

Note : Here we're merging the updated field/document with existing, but not replacing/updating entire document, default behavior of $merge is merge whenMatched document is found, You can pass other options like replace/keepExisting etc.

Ref: $merge