convert iso date to timestamp in mongo query

Question

here is the query

[
    { 
        \"$project\": {
            \"formattedDate\": { 
                \"$dateToString\": { \"format\": \"%Y-%m-%d\", \"date\":         


        

Answer 1

Mongodb 4.0 has introduced $toLong aggregation which convert date to timestamp

db.collection.aggregate([
  { "$project": {
    "createdAt": {
      "$toLong": "$createdAt"
    }
  }}
])

You can try it here