Tasker JavaScriptlet prepending "undefined" in String

I maintain shows, and films from several platforms within an OrgMode File. Now the string you get when sharing from netflix has unnecessary information. I get rid of that with Tasker and a Java Scriptlet.

var endName = astext.search(" auf Netflix gesehen?") -1;
var text = astext.slice(15,endName);
endName = endName+24;
var replacer = astext.slice(0,endName);
var link = String(astext.replace(replacer));

With

as input source from AutoShare Netflix Toast Interception. So far so good, but as I have actually never used JavaScript before I get to a problem I don't really understand. Infront of my string stored in

there is "undefinded" prepended. I don't really know if I mess up JavaScript syntax or if there is something special with the interpreter Tasker is using. This also happens if I instead of "resharing" the link simply print it out via

Task in Tasker