(defn conj-sort-v [v x by] (->> ((fnil conj []) v x) (sort-by by) (vec)))

conj-sort-v is a syntactic sugar to combine conj, sort-by and vec in a single call. Useful only in some very specific cases and not something that should be used lightly.

(conj-sort-v [1 2 3] 4 -)
=> [4 3 2 1]