Implement trailing slash handler as custom Router

modules/reitit-frontend/src/reitit/frontend.cljs

@@ -15,21 +15,37 @@
          (map (juxt keyword #(.get q %)))
          (into {}))))
 
+(defn trailing-slash-router [parent method]
+  (if method
+    ^{:type ::r/router}
+    (reify r/Router
+      (router-name [_]
+        :trailing-slash-handler)
+      (routes [_]
+        (r/routes parent))
+      (compiled-routes [_]
+        (r/compiled-routes parent))
+      (options [_]
+        (r/options parent))
+      (route-names [_]
+        (r/route-names parent))
+      (match-by-path [_ path]
+        (or (r/match-by-path parent path)
+            (if (str/ends-with? path "/")
+              (if (not= method :add)
+                (r/match-by-path parent (subs path 0 (dec (count path)))))
+              (if (not= method :remove)
+                (r/match-by-path parent (str path "/"))))))
+      (match-by-name [_ name]
+        (r/match-by-name parent name)))
+    parent))
+
 (defn match-by-path
   "Given routing tree and current path, return match with possibly
   coerced parameters. Returns nil if no match found."
   [router path]
-  (let [uri (.parse Uri path)
+  (let [uri (.parse Uri path)]
-        path (.getPath uri)]
+    (if-let [match (r/match-by-path router (.getPath uri))]
-    (if-let [match (or (r/match-by-path router path)
-                       (if-let [trailing-slash-handling (:trailing-slash-handling (r/options router))]
-                         ;; TODO: Maybe the original path should be added under some key in match,
-                         ;; so it is easy for user to see if trailing slash "redirect" happened?
-                         (if (str/ends-with? path "/")
-                           (if (not= trailing-slash-handling :add)
-                             (r/match-by-path router (subs path 0 (dec (count path)))))
-                           (if (not= trailing-slash-handling :remove)
-                             (r/match-by-path router (str path "/"))))))]
       ;; User can update browser location in on-navigate call using replace-state
       (let [q (query-params uri)
             match (assoc match :query-params q)
@@ -62,7 +78,8 @@
   ([raw-routes]
    (router raw-routes {}))
   ([raw-routes opts]
-   (r/router raw-routes (merge {:compile rc/compile-request-coercers} opts))))
+   (-> (r/router raw-routes (merge {:compile rc/compile-request-coercers} opts))
+       (trailing-slash-router (:trailing-slash-handling opts)))))
 
 (defn match-by-name!
   "Logs problems using console.warn"

test/cljs/reitit/frontend/core_test.cljs

@@ -12,10 +12,11 @@
 
 (deftest match-by-path-test
   (testing "simple"
-    (let [router (r/router ["/"
+    (let [router (rf/router
-                            ["" ::frontpage]
+                   ["/"
-                            ["foo" ::foo]
+                    ["" ::frontpage]
-                            ["bar" ::bar]])]
+                    ["foo" ::foo]
+                    ["bar" ::bar]])]
       (is (= (r/map->Match
                {:template "/"
                 :data {:name ::frontpage}
@@ -51,10 +52,11 @@
                      (rf/match-by-name! router ::asd)))))))))
 
   (testing "schema coercion"
-    (let [router (r/router ["/"
+    (let [router (rf/router
-                            [":id" {:name ::foo
+                   ["/"
-                                    :parameters {:path {:id s/Int}
+                    [":id" {:name ::foo
-                                                 :query {(s/optional-key :mode) s/Keyword}}}]]
+                            :parameters {:path {:id s/Int}
+                                         :query {(s/optional-key :mode) s/Keyword}}}]]
                            {:compile rc/compile-request-coercers
                             :data {:coercion rsc/coercion}})]
 
@@ -108,11 +110,12 @@
 
 (deftest trailing-slash-handling-test
   (testing ":both"
-    (let [router (r/router ["/"
+    (let [router (rf/router
-                            ["" ::frontpage]
+                   ["/"
-                            ["foo" ::foo]
+                    ["" ::frontpage]
-                            ["bar/" ::bar]]
+                    ["foo" ::foo]
-                           {:trailing-slash-handling :both})]
+                    ["bar/" ::bar]]
+                            {:trailing-slash-handling :both})]
       (is (= (r/map->Match
                {:template "/foo"
                 :data {:name ::foo}
@@ -136,10 +139,11 @@
              (rf/match-by-path router "/bar"))) ))
 
   (testing ":add"
-    (let [router (r/router ["/"
+    (let [router (rf/router
-                            ["" ::frontpage]
+                   ["/"
-                            ["foo" ::foo]
+                    ["" ::frontpage]
-                            ["bar/" ::bar]]
+                    ["foo" ::foo]
+                    ["bar/" ::bar]]
                            {:trailing-slash-handling :add})]
       (is (= (r/map->Match
                {:template "/foo"
@@ -164,10 +168,11 @@
              (rf/match-by-path router "/bar")))))
 
   (testing ":remove"
-    (let [router (r/router ["/"
+    (let [router (rf/router
-                            ["" ::frontpage]
+                   ["/"
-                            ["foo" ::foo]
+                    ["" ::frontpage]
-                            ["bar/" ::bar]]
+                    ["foo" ::foo]
+                    ["bar/" ::bar]]
                            {:trailing-slash-handling :remove})]
       (is (= (r/map->Match
                {:template "/foo"