Hi there, we’ve included only the brackets and parentheses for the relevant s-expression in order to ensure that they are all balanced.
Since this is a single reitit route declaration, it is the vector ["/message" ...] which is meant to be inserted into (defn service-routes [] ["/api" ... ]) wherever the reader wishes. We just happened to insert it at the end in the source. The closing bracket and parenthesis are part of the outer function and vector so they are not included.
Hope this helps. Glad you’re enjoying the book. Thanks for reading!