enhance(rtc): add ns frontend.worker.rtc.hash

src/main/frontend/worker/rtc/hash.cljs

@@ -0,0 +1,29 @@
+(ns frontend.worker.rtc.hash
+  "Calculate the hash of the blocks to compare whether
+  these blocks are consistent with the remote.")
+
+(defn- block-entity->str
+  "Convert block-entity to a string(concat by values selected by :selected-keys).
+  'selected-keys':  it's a ordered coll"
+  [selected-keys block-entity]
+  (->> selected-keys
+       (reduce
+        (fn [r k-or-ks]
+          (let [v (if (sequential? k-or-ks)
+                    (get-in block-entity k-or-ks)
+                    (get block-entity k-or-ks))]
+            (if (nil? v)
+              (reduced nil)
+              (conj r v))))
+        [])
+       (apply str)))
+
+
+(defn hash-blocks
+  [block-entities & {:keys [selected-keys]
+                     :or {selected-keys [:block/uuid
+                                         [:block/left :block/uuid]
+                                         [:block/parent :block/uuid]]}}]
+  (let [str-set (set (keep (partial block-entity->str selected-keys) block-entities))]
+    {:hash (hash str-set)
+     :count (count str-set)}))