[fixed] Allow comments in JSX config

Fixes remix-run#672

modules/__tests__/Router-test.js

@@ -830,20 +830,6 @@ describe('Router.run', function () {
     });
   });
 
-  it('does not break on falsy routes', function (done) {
-    var routes = [
-      <Route handler={Foo} path="/foo"/>,
-      null,
-      <Route handler={Bar} path="/bar"/>,
-      undefined
-    ];
-    Router.run(routes, '/foo', function (Handler, state) {
-      var html = React.renderToString(<Handler/>);
-      expect(html).toMatch(/Foo/);
-      done();
-    });
-  });  
-
   it('matches nested routes', function (done) {
     var routes = (
       <Route handler={Nested} path='/'>

modules/__tests__/createRoutesFromReactChildren-test.js

@@ -0,0 +1,37 @@
+var expect = require('expect');
+var React = require('react');
+var Router = require('../index');
+var Route = require('../components/Route');
+var { Foo, Bar, Nested } = require('../utils/TestHandlers');
+
+describe('creating routes from ReactChildren', function () {
+  it('works with falsy children', function (done) {
+    var routes = [
+      <Route handler={Foo} path="/foo"/>,
+      null,
+      <Route handler={Bar} path="/bar"/>,
+      undefined
+    ];
+
+    Router.run(routes, '/foo', function (Handler, state) {
+      var html = React.renderToString(<Handler/>);
+      expect(html).toMatch(/Foo/);
+      done();
+    });
+  });
+
+  it('works with comments', function (done) {
+    var routes = [
+      <Route handler={Nested} path="/foo">
+        // This is a comment.
+        <Route handler={Bar} path="/bar"/>
+      </Route>
+    ];
+
+    Router.run(routes, '/bar', function (Handler, state) {
+      var html = React.renderToString(<Handler/>);
+      expect(html).toMatch(/Bar/);
+      done();
+    });
+  });
+});

modules/createRoutesFromReactChildren.js

@@ -149,7 +149,7 @@ function createRoutesFromReactChildren(children, parentRoute, namedRoutes) {
 
   React.Children.forEach(children, function (child) {
     // Exclude null values, <DefaultRoute>s and <NotFoundRoute>s.
-    if (child && (child = createRoute(child, parentRoute, namedRoutes)))
+    if (React.isValidElement(child) && (child = createRoute(child, parentRoute, namedRoutes)))
       routes.push(child);
   });