How can I determine if a variable exists from within the Groovy code running in the Scripting Engine?

Question

How can I determine if a variable exists from within the Groovy code running in the Scripting Engine?

The variable was put by ScriptEngine's put method

Answer 1

Improvement for the existing solution given here https://stackoverflow.com/a/56306660/3158217 -

def defaultIfInexistent(varName, defaultValue){
    try{
        varName.toString()
        return varName
    }catch(ex){
        return defaultValue
    }
}