MongoDB - Use field in the document as regex expression

Question

I am storing regex expressions in MongoDB and would like to use them for queries.

Documents structure:

{
    "name": "foo",
    "regex_expression": "^[^@ ]+@(bar\.com)$"
}

I tried the following query but it doesn't work.

db.collection.find({$expr: {$regex: ["foo@bar.com", "$regex_expression]}})

Is it possible to do this kind of query?

user_8017690 · Answer

You need the $regexMatch operator.

db.collection.find({
  $expr: {
    $regexMatch: {
      input: "foo@bar.com",
      regex: "$regex_expression"
    }
  }
})