Custom type or how to use valueGetter

I'm using QueryBuilder to create queries for a MongoDB collection. One of the fields in the documents in the collection is amount and it's defined as Decimal128. In order to query it the value needs to be wrapped in NumberDecimal() like:

db.getCollection('transactions').find({"$and":[{"amount":NumberDecimal(99.02)}]})

Is it possible to create a custom type to QueryBuilder applies this to fields where this is necessary?

I tried using valueGetter but it's not working. My filter looks like:

{
  id: 'amount',
  type: 'double',
  valueGetter: (rule) => {
    return `NumberDecimal(${rule.$el.find('[name*=_value_]').val()})`
  }
}

If I debug the valueGetter it's returning what I would expect (NumberDecimal(99.02)) but when I get the rules I get null.

I guess I could change the type to string but then I'd also have to change all the operators to the numeric operators.

Is there a better way to do this?

Start with the QueryBuilder type configuration and the valueGetter entry point shown in the issue, then trace how rules are serialized after valueGetter returns. Reproduce the amount filter with the MongoDB output, and consider the work complete when a Decimal128 value is preserved as NumberDecimal(...) while numeric operators remain available.