Can JMeter extract values of variables that are not explicitly stated inside JavaScript code?

I'm using JMeter to load test a website built almost entirely in JavaScript/AngularJS/Java. There are a few dynamic parameters that the page uses as part of its login, that I need to be able to read every time each thread attempts logging in, and pass along throughout the rest of the process. However, these parameters are not explicitly declared in the HTML code of the webpage, so I don't think the RegEx extractor would be of much help here. They are only mentioned in a JS script that is sent along with the HTTP response and called through another script, which is in turned called by the HTML body of the page. The value is never explicitly stated in the script, it is only mentioned in sentences such as:

return c.tokenVal=n,f;

And similarly, n and f are only mentioned but never explicitly declared. Is there a way for JMeter to be able to obtain the value of these parameters (of tokenVal, in this example)?