I want to know how to improve my front-end web dev skills besides from "learn-by-doing". I work as a front-end developer and I learn by doing all the time. I want to learn the theory to be prepared so that I don't have to learn by doing. The technologies I want to learn are less, sass and more javascript (jquery, extjs/sencha), front-end testing etc. I.e. everything it takes to become a better front-end developer without just learning by solving practical problem, which I already do.
I know book recommendations are usually off-topic on SE sites, can I still ask a question like this?
