#9: Implement zipper support

Author: askonomm

src/dompa/nodes.cljc

@@ -1,4 +1,5 @@
-(ns dompa.nodes)
+(ns dompa.nodes
+  (:require [clojure.zip :as zip]))
 
 (def ^:private default-void-nodes
   #{:!doctype :!DOCTYPE :area :base :br :col :embed :hr :img :input
@@ -50,6 +51,18 @@
           updated-nodes))
       (reduce [] nodes)))
 
+(defn zip
+  "Creates a zipper for given a given `node`."
+  [node]
+  (zip/zipper
+    (fn branch? [node]
+      (boolean (seq (:node/children node))))
+    (fn children [node]
+      (:node/children node))
+    (fn make-node [node children]
+      (assoc node :node/children children))
+    node))
+
 (defn ->html
   "Transform a vector of `nodes` into an HTML string.
 

test/dompa/nodes_test.cljc

@@ -1,9 +1,12 @@
 (ns dompa.nodes-test
-  #?(:clj (:require [clojure.test :refer [deftest is testing]]
-                    [dompa.nodes :refer [$ defhtml traverse ->html]]
-                    [dompa.html :as html]))
+  #?(:clj (:require
+           [clojure.test :refer [deftest is testing]]
+           [clojure.zip :as zip]
+           [dompa.html :as html]
+           [dompa.nodes :as nodes :refer [$ defhtml]]))
   #?(:cljs (:require [cljs.test :refer-macros [deftest testing is]]
-                     [dompa.nodes :refer [$ traverse ->html] :refer-macros [defhtml]]
+                     [clojure.zip :as zip]
+                     [dompa.nodes :as nodes :refer [$] :refer-macros [defhtml]]
                      [dompa.html :as html])))
 
 (defhtml hello [who]
@@ -18,7 +21,7 @@
   ($ :ul
      (->> items
           (map (fn [item]
-                ($ :li ($ item))))
+                 ($ :li ($ item))))
           (into []))))
 
 (deftest list-items-test
@@ -53,5 +56,17 @@
                          node))]
     (is (= "<div>world hello</div>"
            (-> (html/->nodes "<div>hello world</div>")
-               (traverse traverser-fn)
-               ->html)))))
+               (nodes/traverse traverser-fn)
+               nodes/->html)))))
+
+(deftest zip-test
+  (let [nodes (html/->nodes "<div><p>hello</p><p>world</p></div>")
+        zipper (nodes/zip (first nodes))]
+    (is (= :div
+           (:node/name (zip/node zipper))))
+    (is (= "hello"
+           (-> zipper
+               zip/down
+               zip/down
+               zip/node
+               :node/value)))))