[ { $match: { $and: [ { "age": { $type: "string" } }, { $expr: { $gt: [{ $strLenCP: "$age" }, 5] } } ] } }, { $project: { email:1 } } ]
[ { $match: { $and: [ { "age": { $type: "string" } }, { $expr: { $gt: [{ $strLenCP: "$age" }, 5] } } ] } }, { $project: { email:1 } } ]