isNullType

%dw 2.0
import * from dw::core::Types
type ANull = Null
output application/json
---
{
   a: isNullType(ANull),
   b: isNullType(Null),
   c: isNullType(String),
}

{
  "a": true,
  "b": true,
  "c": false
}