Cleans a map to remove nil, empty and false values

clean.clj

(defn filter-map
  "Returns a map with only the pairs that (pred key value) returned true"
  [pred m]
  (select-keys m (filter #(pred % (m %)) (keys m))))

(defn clean-map
  "Takes a map and removes all nil's, empty data structs, and
   falses as these can be implied by them not being there."
  [m]
  (filter-map (fn [key val] (if (or (true? val)
                                    (and val
                                         (or (string? val) (seq? val) (vector? val) (map? val) (set? val))
                                         (not (empty? val)))))) m))