JavaScript autoStoreScriptVariables

In the documentation:

prefix all script variables that should not be stored as script variables using the def keyword: def sum = 0. In this case the variable sum will not be stored as process variable.

the def keyword is for groovy scripting language.

How do we achieve the equivalent things in javaScript (i.e. avoid specific script variable to be stored as process variable) when enabling the autoStoreScriptVariables properties?

If it’s not supported yet, can we get this as a feature request?

Thanks