Merge pull request #704 from reactjs/error-handling

feat(ujs) show errors when component can't be loaded

Author: Robert Mosolgo

lib/assets/javascripts/react_ujs.js

@@ -185,9 +185,14 @@ module.exports = function(reqctx) {
     try {
       // `require` will raise an error if this className isn't found:
       component = fromCtx(className)
-    } catch (err) {
+    } catch (firstErr) {
       // fallback to global:
-      component = fromGlobal(className)
+      try {
+        component = fromGlobal(className)
+      } catch (secondErr) {
+        console.error(firstErr)
+        console.error(secondErr)
+      }
     }
     return component
   }

react_ujs/dist/react_ujs.js

@@ -185,9 +185,14 @@ module.exports = function(reqctx) {
     try {
       // `require` will raise an error if this className isn't found:
       component = fromCtx(className)
-    } catch (err) {
+    } catch (firstErr) {
       // fallback to global:
-      component = fromGlobal(className)
+      try {
+        component = fromGlobal(className)
+      } catch (secondErr) {
+        console.error(firstErr)
+        console.error(secondErr)
+      }
     }
     return component
   }

react_ujs/src/getConstructor/fromRequireContextWithGlobalFallback.js

@@ -11,9 +11,14 @@ module.exports = function(reqctx) {
     try {
       // `require` will raise an error if this className isn't found:
       component = fromCtx(className)
-    } catch (err) {
+    } catch (firstErr) {
       // fallback to global:
-      component = fromGlobal(className)
+      try {
+        component = fromGlobal(className)
+      } catch (secondErr) {
+        console.error(firstErr)
+        console.error(secondErr)
+      }
     }
     return component
   }

test/react/server_rendering/bundle_renderer_test.rb

@@ -68,7 +68,13 @@ class BundleRendererTest < ActiveSupport::TestCase
         @renderer.render("NonExistentComponent", {}, nil)
       end
 
-      assert_match(/ReferenceError/, err.to_s)
+      if WebpackerHelpers.available?
+        # require() failed:
+        assert_match(/Invariant Violation: Element type is invalid: expected a string/, err.to_s)
+      else
+        # eval() failed:
+        assert_match(/ReferenceError/, err.to_s)
+      end
       assert_match(/NonExistentComponent/, err.to_s, "it names the component")
 
       assert_match(/\n/, err.to_s, "it includes the multi-line backtrace")