These are just some things that seemed slightly odd - not errors per se - just things that just were confusing to me a bit that might be redone if possible to make it clearer.
Why is this named hero? Because function components are heroic perhaps!
def hero(assigns) do
Next is the code listing on pages 189 and 190. No errors in there however note that the list function is fully baked there. Then at the bottom of 190 through 191 it appears again in a less developed form and the prose builds on it from there. Naturally I had already keyed in the fully baked one by this point and was like wait a sec… Maybe it would be better to just leave the completed one out altogether until the end.