Fixes read-handlers with multiple arities (closes cognitect#49)

tonsky · Oct 21, 2024 · 4bcf345 · 4bcf345
1 parent 3d8a2c4
commit 4bcf345
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Showing 2 changed files with 47 additions and 15 deletions.
diff --git a/src/cognitect/transit.cljs b/src/cognitect/transit.cljs
@@ -115,21 +115,23 @@
      (t/reader (name type)
        (opts-merge
          #js {:handlers
-              (clj->js
-                (merge
-                  {"$"    (fn [v] (symbol v))
-                   ":"    (fn [v] (keyword v))
-                   "set"  (fn [v] (into #{} v))
-                   "list" (fn [v] (into () (.reverse v)))
-                   "cmap" (fn [v]
-                            (loop [i 0 ret (transient {})]
-                              (if (< i (alength v))
-                                (recur (+ i 2)
-                                  (assoc! ret (aget v i) (aget v (inc i))))
-                                (persistent! ret))))
-                   "with-meta"
-                          (fn [v] (with-meta (aget v 0) (aget v 1)))}
-                  (dissoc (:handlers opts) :default)))
+              (reduce-kv
+                (fn [m tag handler]
+                  (gobj/set m (clj->js tag) #(handler %))
+                  m)
+                #js {"$"    (fn [v] (symbol v))
+                     ":"    (fn [v] (keyword v))
+                     "set"  (fn [v] (into #{} v))
+                     "list" (fn [v] (into () (.reverse v)))
+                     "cmap" (fn [v]
+                              (loop [i 0 ret (transient {})]
+                                (if (< i (alength v))
+                                  (recur (+ i 2)
+                                    (assoc! ret (aget v i) (aget v (inc i))))
+                                  (persistent! ret))))
+                     "with-meta"
+                            (fn [v] (with-meta (aget v 0) (aget v 1)))}
+                (dissoc (:handlers opts) :default))
               :defaultHandler (-> opts :handlers :default)
               :mapBuilder (MapBuilder.)
               :arrayBuilder (VectorBuilder.)

diff --git a/test/transit/test/core.cljs b/test/transit/test/core.cljs
@@ -131,6 +131,36 @@
   (is (= (t/read cr "[\"~:foo\", 1]")
          [:foo 1])))
 
+(deftest test-read-custom-arities
+  (is (= (t/read (t/reader :json
+                   {:handlers
+                    {"custom" (fn [x]
+                                x)}})
+           "[\"~#custom\",\"abc\"]")
+        "abc"))
+  (is (= (t/read (t/reader :json 
+                   {:handlers
+                    {"custom" (fn
+                                ([] nil)
+                                ([x] x))}})
+           "[\"~#custom\",\"abc\"]")
+        "abc"))
+  (is (= (t/read (t/reader :json 
+                   {:handlers
+                    {"custom" (fn
+                                ([x] x)
+                                ([x y] [x y]))}})
+           "[\"~#custom\",\"abc\"]")
+        "abc"))
+  (is (= (t/read (t/reader :json 
+                   {:handlers
+                    {"custom" (fn
+                                ([] nil)
+                                ([x] x)
+                                ([x y] [x y]))}})
+           "[\"~#custom\",\"abc\"]")
+        "abc")))
+
 (def cw
   (t/writer :json
     {:handlers