Calling js functions in Twine 2 Sugarcube without macros, is it possible?

I've been attaching js functions to the global window object, and I'm able to call them:

-when setting a return type to a variable

<<set $var to myFunction()>>

-or when going to another passage

[[nextPassage][myFunction()]]

However, just calling my function, without a return value, is not possible.

<<myFunction()>>  //error!  must define myFunction() as a macro.

Is setting a macro the only way to call functions like this is Sugarcube? Thanks.