It really depends where you are in your career. If you are just starting out and would like to work in general web development, committing yourself to JS only w

It really depends where you are in your career. If you are just starting out and would like to work in general web development, committing yourself to JS only would be stupid beyond belief. That would assume that JS based frameworks are going to be ubiquitous in the near future. They definitely won't be and there are many reasons to doubt that they will be ubiquitous in the long term as well. The same can be said for any language or framework, language convergence does not seem to be happening. More likely the landscape will remain unstable in the medium to long term. Therefore, as a generalist web developer you will be better served by polyglotism. Learn MVC and other application design patterns. Learn server side programming and client side programming. Learn SQL and others ways of interfacing with persistence layers. In short, don't stop learning and don't assume that there is one holy grail or one right way to do it. There are many jobs and many tools. Being a good programmer is about finding a way to match the tools with the job.