Add componentDidCatch support and test (error boundary)

src/reagent/impl/component.cljs

@@ -199,6 +199,10 @@
                (when-not (nil? f)
                  (.call f c c))))
 
+    :componentDidCatch
+    (fn componentDidCatch [error info]
+      (this-as c (.call f c c error info)))
+
     nil))
 
 (defn get-wrapper [key f name]
@@ -268,9 +272,11 @@
        create-react-class))
 
 (defn component-path [c]
-  (let [elem (some-> (or (some-> c ($ :_reactInternalInstance))
+  ;; Looks like in React 16, reactInternalFiber is the elem
+  (let [elem (or (some-> c ($ :_reactInternalFiber))
+                 (some-> (or (some-> c ($ :_reactInternalInstance))
                              c)
-                     ($ :_currentElement))
+                         ($ :_currentElement)))
         name (some-> elem
                      ($ :type)
                      ($ :displayName))

test/reagenttest/testreagent.cljs

@@ -1,5 +1,6 @@
 (ns reagenttest.testreagent
   (:require [cljs.test :as t :refer-macros [is deftest testing]]
+            [react :as react]
             [create-react-class :as create-react-class]
             [reagent.ratom :as rv :refer-macros [reaction]]
             [reagent.debug :as debug :refer-macros [dbg println log dev?]]
@@ -964,6 +965,26 @@
           (is (re-find #"Every element in a seq should have a unique :key"
                        (-> e :warn first))))))))
 
+(deftest test-error-boundary
+  (when (>= (js/parseInt react/version) 16)
+    (let [error (r/atom nil)
+          error-boundary (fn error-boundary [comp]
+                           (r/create-class
+                             {:component-did-catch (fn [this e info]
+                                                     (reset! error e))
+                              :reagent-render (fn [comp]
+                                                (if @error
+                                                  [:div "Something went wrong."]
+                                                  comp))}))
+          comp1 (fn comp1 []
+                  ($ nil :foo)
+                  [:div "foo"])]
+      (with-mounted-component [error-boundary [comp1]]
+        (fn [c div]
+          (r/flush)
+          (is (= "Cannot read property 'foo' of null" (.-message @error)))
+          (is (found-in #"Something went wrong\." div)))))))
+
 (deftest test-dom-node
   (let [node (atom nil)
         ref (atom nil)