AVAILABLE NOW: Front-End Developer Handbook 2017
Part II: Learning
Part two identifies self-directed (i.e., at your own pace when you want) and directed (i.e., formal class room specific times and dates) resources for learning to become a front-end developer.
Note that just because a learning resource is listed, or a category of learning is documented, I am not suggesting that a front-end developer learn everything. That would be absurd. Choose your own slice of expertise within the profession. I'm providing the possibilities of what could be mastered in the field.