Converts a value to a long. If the value cannot be converted to a long, $toLong errors. If the value is null or missing, $toLong returns null.
4.0
https://www.mongodb.com/docs/manual/reference/operator/aggregation/toInt/#mongodb-expression-exp.-toInt
Converts a value to a long. If the value cannot be converted to a long, $toLong errors. If the value is null or missing, $toLong returns null.