JavaScript skills are much more important in an SPA then in a traditional web applications. Most of the application will be in JavaScript instead of
Java, Ruby, or some other server side language. Next is being open to learning a new
pattern of writing code. Most languages and web frameworks follow a very familiar server side MVC pattern. Rails and Spring MVC have more in common then they are different. We still follow an MVC pattern in our book for an SPA, but we follow it on the client side as well.