I've been following GWT from a distance, which is to say we have not used it yet. From what I understand of it so far, it seems to solve a lot of problems (though what new technology doesn't?)
My question is: How much js knowledge is required to understand the book contents and examples? How much js knowledge should we have before making effective use of GWT? Bottom line, is learning js a worthwhile goal in a GWT framework?
In my view, to get going with GWT you just need to have a passable knowledge of:
As you get going further into GWT then you might start focussing on one or more of those issues in more depth as you need.
Hope that helps!