please read the last post in this Thread, where you already posted the same question:
Calling a connector function from within a custom widget? - Custom Widgets - Tulip Community
You can also use console.log(outputVal); however this is no output to your TULIP Application but to your Browser Console (is this what you want? what is the use case?).
For custom Widget basics (input and output handling) also read: Custom Widgets Overview (tulip.co)