This is one of the those questions that is highly subjective and will continue to bubble for many more years, I’m sure. But at the end of the day, anyone who ask’s themselves this question needs to realise how important it is to their career.
If you want to be more employable as a designer who primarily designs for the web, then learn code (front end). If Joe Bloggs went for a new position as a UI designer, but so does Jane Doe, but Jane Doe know’s how to code……if both conducted themselves well during the interview, I know who I would bet on getting the job!!
I’ve always considered myself as a ‘hybrid’ — a designer who can code! I’m a front-end Designer who understands the limitations of what a front-end developer can do…..and boy, we can do a LOT nowadays!
From my own personal point of view, if I can spend a few days in Sketch or Photoshop and then another few days deep in front-end coding…….not only I’m I responsible for bringing my creations to life, I’m also more content in my role ;-)