merge maps into a unified one map.

merge-maps.cljs

(defn merge-maps [& maps]
  ;; (sanitize-map)
  (if (every? map? maps)
    (apply merge-with merge-maps maps)
    (last maps)))

(defn sanitize-map [m]
  (if (map? m)
    (let [clean-val (fn [[k v]]
                      (let [v' (sanitize-map v)]
                        (when-not (nil? v')
                          [k v'])))
          m' (->> (map clean-val m)
                  (remove nil?)
                  (into {}))]
      (when-not (empty? m') m')) m))

(def json {:k1 "k1" :k2 "k2" :k5 "k5"})
(def json2 {:k2 "k2" :k3 "k3" :k10 nil}) 
(def json3 {:a "a" :b "b"})

json
json2

(merge-maps json json2)
;; {:k1 "k1", :k2 "k2", :k5 "k5", :k3 "k3", :k10 nil}

(merge-maps json json2 json3)
;; {:k1 "k1", :k2 "k2", :k5 "k5", :k3 "k3", :k10 nil, :a "a", :b "b"}

(merge-maps json json2 {:test "test" :test2 "test2" :inside {:in1 "in1" :in2 "in2"}}
;; {:k1 "k1", :k2 "k2", :k5 "k5", :k3 "k3", :k10 nil, :test "test", :test2 "test2", :inside {:in1 "in1", :in2 "in2"}}

;; TODO: 
;; 0. allow nil flag
;; 1. flatten nested map flag
;; 2. what else?

;; (defn merge-maps 
;;    [& {:keys [& maps allowNil?] :or { allowNil? true }}]
;;    (defn sanitize-map [m]
;;      (if (map? m)
;;        (let [clean-val (fn [[k v]]
;;                          (let [v' (sanitize-map v)]
;;                            (when-not (nil? v')
;;                              [k v'])))
;;              m' (->> (map clean-val m)
;;                      (remove nil?)
;;                      (into {}))]
;;          (when-not (empty? m') m')) m))
   
;;    (if allowNil?
;;      (if (every? map? maps)
;;        (apply merge-with merge-maps :maps maps :allowNil? allowNil?)
;;        (last maps))
     
;;      (sanitize-map
;;       (if (every? map? maps)
;;         (apply merge-with merge-maps :maps maps :allowNil? allowNil?)
;;         (last maps))))))

;; (def json {:k1 "k1" :k2 "k2" :k5 "k5"})
;; (def json2 {:k2 "k2" :k3 "k3" :k10 nil})
  
;; json
;; json2

;; (merge-maps :maps json json2)