Add support for frontend:// using separate es5 and es6 folders

15 files changed, 426 insertions, 10 deletions

diff --git a/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java b/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java
index 14f9b34486..bf521a198c 100644
--- a/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java
+++ b/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java
@@ -238,6 +238,7 @@ public class ApplicationConfiguration implements EntryPoint {
      * always end with a slash (/).
      */
     private String vaadinDirUrl;
+    private String frontendUrl;
     private String serviceUrl;
     private String contextRootUrl;
     private int uiId;
@@ -339,6 +340,16 @@ public class ApplicationConfiguration implements EntryPoint {
         return vaadinDirUrl;
     }
 
+    /**
+     * Gets the URL of the that the {@literal frontend://} protocol should
+     * resolve to.
+     *
+     * @return the URL of the frontend protocol
+     */
+    public String getFrontendUrl() {
+        return frontendUrl;
+    }
+
     public void setAppId(String appId) {
         id = appId;
     }
@@ -427,6 +438,8 @@ public class ApplicationConfiguration implements EntryPoint {
                 .getConfigString(ApplicationConstants.CONTEXT_ROOT_URL);
         vaadinDirUrl = WidgetUtil.getAbsoluteUrl(jsoConfiguration
                 .getConfigString(ApplicationConstants.VAADIN_DIR_URL));
+        frontendUrl = WidgetUtil.getAbsoluteUrl(jsoConfiguration
+                .getConfigString(ApplicationConstants.FRONTEND_URL));
         uiId = jsoConfiguration.getConfigInteger(UIConstants.UI_ID_PARAMETER)
                 .intValue();
 
diff --git a/client/src/main/java/com/vaadin/client/ApplicationConnection.java b/client/src/main/java/com/vaadin/client/ApplicationConnection.java
index e94195cd37..6f2a78a2d5 100644
--- a/client/src/main/java/com/vaadin/client/ApplicationConnection.java
+++ b/client/src/main/java/com/vaadin/client/ApplicationConnection.java
@@ -334,6 +334,13 @@ public class ApplicationConnection implements HasHandlers {
         protected String getContextRootUrl() {
             return getConfiguration().getContextRootUrl();
         }
+
+        @Override
+        protected String getFrontendUrl() {
+            String url = getConfiguration().getFrontendUrl();
+            assert url.endsWith("/");
+            return url;
+        }
     };
 
     public static class MultiStepDuration extends Duration {
diff --git a/server/src/main/java/com/vaadin/annotations/HtmlImport.java b/server/src/main/java/com/vaadin/annotations/HtmlImport.java
index 81b4db87ca..dd20558737 100644
--- a/server/src/main/java/com/vaadin/annotations/HtmlImport.java
+++ b/server/src/main/java/com/vaadin/annotations/HtmlImport.java
@@ -40,8 +40,10 @@ import com.vaadin.server.ClientConnector;
  * <li>Absolute URLs including protocol and host are used as is on the
  * client-side.
  * </ul>
- * Note that it is a good idea to use URLs starting with {@literal vaadin://}
- * and place all HTML imports inside {@literal VAADIN/bower_components}. Polymer
+ * Note that you should (almost) always use URLs starting with
+ * {@literal frontend://} so that the framework can resolve the files to either
+ * {@literal VAADIN/es5} or {@literal VAADIN/es6} depending on if the browser
+ * supports ES6 classes (most browers) or not (IE11 and Safari <= 9). Polymer
  * elements rely on importing dependencies using relative paths
  * {@literal ../../other-element/other-element.html}, which will not work if
  * they are installed in different locations.
@@ -50,10 +52,10 @@ import com.vaadin.server.ClientConnector;
  * added at the same time.
  * <p>
  * Example:
- * <code>@HtmlImport("bower_components/paper-slider/paper-slider.html")</code>
- * on the class com.example.MyConnector would load the file
- * http://host.com/VAADIN/bower_components/paper-slider/paper-slider.html before
- * the {@code init()} method of the client side connector is invoked.
+ * <code>@HtmlImport("frontend://paper-slider/paper-slider.html")</code> on the
+ * class com.example.MyConnector would load the file
+ * {@literal http://host.com/VAADIN/es[56]/paper-slider/paper-slider.html}
+ * before the {@code init()} method of the client side connector is invoked.
  *
  * @author Vaadin Ltd
  * @since 8.0
diff --git a/server/src/main/java/com/vaadin/server/BootstrapHandler.java b/server/src/main/java/com/vaadin/server/BootstrapHandler.java
index 218ed394cb..2832ecb326 100644
--- a/server/src/main/java/com/vaadin/server/BootstrapHandler.java
+++ b/server/src/main/java/com/vaadin/server/BootstrapHandler.java
@@ -84,7 +84,7 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
         private String appId;
         private PushMode pushMode;
         private JsonObject applicationParameters;
-        private VaadinUriResolver uriResolver;
+        private BootstrapUriResolver uriResolver;
         private WidgetsetInfo widgetsetInfo;
 
         public BootstrapContext(VaadinResponse response,
@@ -177,7 +177,7 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
             return applicationParameters;
         }
 
-        public VaadinUriResolver getUriResolver() {
+        public BootstrapUriResolver getUriResolver() {
             if (uriResolver == null) {
                 uriResolver = new BootstrapUriResolver(this);
             }
@@ -186,8 +186,9 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
         }
     }
 
-    private class BootstrapUriResolver extends VaadinUriResolver {
+    protected static class BootstrapUriResolver extends VaadinUriResolver {
         private final BootstrapContext context;
+        private String frontendUrl;
 
         public BootstrapUriResolver(BootstrapContext bootstrapContext) {
             context = bootstrapContext;
@@ -250,6 +251,28 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
             assert root.endsWith("/");
             return root;
         }
+
+        @Override
+        protected String getFrontendUrl() {
+            if (frontendUrl == null) {
+                DeploymentConfiguration configuration = context.getSession()
+                        .getConfiguration();
+                if (context.getSession().getBrowser().isEs6Supported()) {
+                    frontendUrl = configuration.getApplicationOrSystemProperty(
+                            ApplicationConstants.FRONTEND_URL_ES6,
+                            ApplicationConstants.FRONTEND_URL_ES6_DEFAULT_VALUE);
+                } else {
+                    frontendUrl = configuration.getApplicationOrSystemProperty(
+                            ApplicationConstants.FRONTEND_URL_ES5,
+                            ApplicationConstants.FRONTEND_URL_ES5_DEFAULT_VALUE);
+                }
+                if (!frontendUrl.endsWith("/")) {
+                    frontendUrl += "/";
+                }
+            }
+
+            return frontendUrl;
+        }
     }
 
     @Override
@@ -708,6 +731,8 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
         String vaadinDir = vaadinService.getStaticFileLocation(request)
                 + "/VAADIN/";
         appConfig.put(ApplicationConstants.VAADIN_DIR_URL, vaadinDir);
+        appConfig.put(ApplicationConstants.FRONTEND_URL,
+                context.getUriResolver().getFrontendUrl());
 
         if (!session.getConfiguration().isProductionMode()) {
             appConfig.put("debug", true);
diff --git a/server/src/main/java/com/vaadin/server/WebBrowser.java b/server/src/main/java/com/vaadin/server/WebBrowser.java
index f7fbea6513..5c387d0c14 100644
--- a/server/src/main/java/com/vaadin/server/WebBrowser.java
+++ b/server/src/main/java/com/vaadin/server/WebBrowser.java
@@ -538,4 +538,18 @@ public class WebBrowser implements Serializable {
         return browserDetails.isTooOldToFunctionProperly();
     }
 
+    /**
+     * Checks if the browser supports ECMAScript 6, based on the user agent.
+     *
+     * @return <code>true</code> if the browser supports ES6, <code>false</code>
+     *         otherwise.
+     */
+    public boolean isEs6Supported() {
+        if (browserDetails == null) {
+            // Don't know, so assume no
+            return false;
+        }
+        return browserDetails.isEs6Supported();
+
+    }
 }
diff --git a/server/src/test/java/com/vaadin/server/BootstrapHandlerTest.java b/server/src/test/java/com/vaadin/server/BootstrapHandlerTest.java
new file mode 100644
index 0000000000..3530d105a3
--- /dev/null
+++ b/server/src/test/java/com/vaadin/server/BootstrapHandlerTest.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.server;
+
+import java.util.Properties;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import com.vaadin.server.BootstrapHandler.BootstrapContext;
+import com.vaadin.server.BootstrapHandler.BootstrapUriResolver;
+
+public class BootstrapHandlerTest {
+
+    private static final String VAADIN_URL = "http://host/VAADIN/";
+
+    public static class ES5Browser extends WebBrowser {
+        @Override
+        public boolean isEs6Supported() {
+            return false;
+        }
+    }
+
+    public static class ES6Browser extends WebBrowser {
+        @Override
+        public boolean isEs6Supported() {
+            return true;
+        }
+    }
+
+    @Test
+    public void resolveFrontendES5() {
+        testResolveFrontEnd("frontend://foobar.html",
+                "http://host/VAADIN/frontend/es5/foobar.html",
+                new ES5Browser());
+
+    }
+
+    @Test
+    public void resolveFrontendES6() {
+        testResolveFrontEnd("frontend://foobar.html",
+                "http://host/VAADIN/frontend/es6/foobar.html",
+                new ES6Browser());
+
+    }
+
+    @Test
+    public void resolveFrontendES5CustomUrl() {
+        Properties properties = new Properties();
+        properties.setProperty("frontend.url.es5",
+                "https://cdn.somewhere.com/5");
+        testResolveFrontEnd("frontend://foobar.html",
+                "https://cdn.somewhere.com/5/foobar.html", new ES5Browser(),
+                properties);
+
+    }
+
+    @Test
+    public void resolveFrontendES6CustomUrl() {
+        Properties properties = new Properties();
+        properties.setProperty("frontend.url.es6",
+                "https://cdn.somewhere.com/6");
+        testResolveFrontEnd("frontend://foobar.html",
+                "https://cdn.somewhere.com/6/foobar.html", new ES6Browser(),
+                properties);
+
+    }
+
+    private static void testResolveFrontEnd(String frontendUrl,
+            String expectedUrl, WebBrowser browser) {
+        testResolveFrontEnd(frontendUrl, expectedUrl, browser,
+                new Properties());
+    }
+
+    @SuppressWarnings("deprecation")
+    private static void testResolveFrontEnd(String frontendUrl,
+            String expectedUrl, WebBrowser browser,
+            Properties customProperties) {
+
+        BootstrapContext context = Mockito.mock(BootstrapContext.class);
+        BootstrapUriResolver resolver = new BootstrapUriResolver(context) {
+            @Override
+            protected String getVaadinDirUrl() {
+                return VAADIN_URL;
+            }
+        };
+        VaadinSession session = Mockito.mock(VaadinSession.class);
+        Mockito.when(context.getSession()).thenReturn(session);
+        DeploymentConfiguration configuration = new DefaultDeploymentConfiguration(
+                BootstrapHandlerTest.class, customProperties);
+        Mockito.when(session.getBrowser()).thenReturn(browser);
+        Mockito.when(session.getConfiguration()).thenReturn(configuration);
+
+        Assert.assertEquals(expectedUrl,
+                resolver.resolveVaadinUri(frontendUrl));
+    }
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ApplicationConstants.java b/shared/src/main/java/com/vaadin/shared/ApplicationConstants.java
index 17ef828ba5..286cd07760 100644
--- a/shared/src/main/java/com/vaadin/shared/ApplicationConstants.java
+++ b/shared/src/main/java/com/vaadin/shared/ApplicationConstants.java
@@ -45,6 +45,8 @@ public class ApplicationConstants implements Serializable {
     public static final String PUBLISHED_PROTOCOL_NAME = "published";
     public static final String PUBLISHED_PROTOCOL_PREFIX = PUBLISHED_PROTOCOL_NAME
             + "://";
+    public static final String FRONTEND_PROTOCOL_PREFIX = "frontend://";
+
     /**
      * Prefix used for theme resource URLs
      *
@@ -98,6 +100,16 @@ public class ApplicationConstants implements Serializable {
     public static final String VAADIN_DIR_URL = "vaadinDir";
 
     /**
+     * Configuration parameter giving the (in some cases relative) URL to the
+     * frontend resource folder from where frontend files are served (this is
+     * what frontend:// should resolve to).
+     * <p>
+     * By default, this is "vaadin://es6" ("vaadin://es5" for browsers which
+     * does not support ES6).
+     */
+    public static final String FRONTEND_URL = "frontendUrl";
+
+    /**
      * The name of the javascript containing the bootstrap code. The file is
      * located in the VAADIN directory.
      *
@@ -184,4 +196,30 @@ public class ApplicationConstants implements Serializable {
      */
     public static final String CONTENT_TYPE_TEXT_HTML_UTF_8 = "text/html; charset=utf-8";
 
+    /**
+     * Configuration name for the {@literal frontend://} URL when using a
+     * browser which is not ES6 compatible (i.e. IE11 or Safari 9).
+     */
+    public static final String FRONTEND_URL_ES5 = "frontend.url.es5";
+
+    /**
+     * Configuration name for the {@literal frontend://} URL when using an ES6
+     * compatible browser.
+     */
+    public static final String FRONTEND_URL_ES6 = "frontend.url.es6";
+
+    /**
+     * Default value of the configuration of the build URL of ES6 web
+     * components.
+     */
+    public static final String FRONTEND_URL_ES6_DEFAULT_VALUE = VAADIN_PROTOCOL_PREFIX
+            + "frontend/es6/";
+
+    /**
+     * Default value of the configuration of the build URL of ES5 web
+     * components.
+     */
+    public static final String FRONTEND_URL_ES5_DEFAULT_VALUE = VAADIN_PROTOCOL_PREFIX
+            + "frontend/es5/";
+
 }
diff --git a/shared/src/main/java/com/vaadin/shared/VBrowserDetails.java b/shared/src/main/java/com/vaadin/shared/VBrowserDetails.java
index 99dac478bc..c3c1baa582 100644
--- a/shared/src/main/java/com/vaadin/shared/VBrowserDetails.java
+++ b/shared/src/main/java/com/vaadin/shared/VBrowserDetails.java
@@ -149,7 +149,8 @@ public class VBrowserDetails implements Serializable {
                         parseVersionString(tmp);
                     }
                 } else if (isTrident) {
-                    // See https://msdn.microsoft.com/en-us/library/ms537503(v=vs.85).aspx#TriToken
+                    // See
+                    // https://msdn.microsoft.com/en-us/library/ms537503(v=vs.85).aspx#TriToken
                     setIEMode((int) browserEngineVersion + 4);
                 } else {
                     String ieVersionString = userAgent
@@ -585,4 +586,23 @@ public class VBrowserDetails implements Serializable {
         return false;
     }
 
+    public boolean isEs6Supported() {
+        if (isTooOldToFunctionProperly()) {
+            return false;
+        }
+
+        // assumes evergreen browsers support ES6
+        if (isChrome() || isFirefox() || isOpera() || isEdge()) {
+            return true;
+        }
+
+        // Safari > 9
+        if (isSafari() && getBrowserMajorVersion() > 9) {
+            return true;
+        }
+
+        // IE11 and Safari 9
+        return false;
+    }
+
 }
diff --git a/shared/src/main/java/com/vaadin/shared/VaadinUriResolver.java b/shared/src/main/java/com/vaadin/shared/VaadinUriResolver.java
index 5755c686bf..6c02028d8b 100644
--- a/shared/src/main/java/com/vaadin/shared/VaadinUriResolver.java
+++ b/shared/src/main/java/com/vaadin/shared/VaadinUriResolver.java
@@ -45,6 +45,9 @@ public abstract class VaadinUriResolver implements Serializable {
      * RequestHandler} instances.</li>
      * <li><code>vaadin://</code> - resolves to the location of static resouces
      * in the VAADIN directory</li>
+     * <li><code>frontend://</code> - resolves to the location of frontend
+     * (Bower and similar) resources, which might vary depending on the used
+     * browser</li>
      * </ul>
      * Any other URI protocols, such as <code>http://</code> or
      * <code>https://</code> are passed through this method unmodified.
@@ -58,6 +61,13 @@ public abstract class VaadinUriResolver implements Serializable {
         if (vaadinUri == null) {
             return null;
         }
+        if (vaadinUri
+                .startsWith(ApplicationConstants.FRONTEND_PROTOCOL_PREFIX)) {
+            final String frontendUrl = getFrontendUrl();
+            vaadinUri = frontendUrl + vaadinUri.substring(
+                    ApplicationConstants.FRONTEND_PROTOCOL_PREFIX.length());
+        }
+
         if (vaadinUri.startsWith(ApplicationConstants.THEME_PROTOCOL_PREFIX)) {
             final String themeUri = getThemeUri();
             vaadinUri = themeUri + vaadinUri.substring(7);
@@ -172,4 +182,13 @@ public abstract class VaadinUriResolver implements Serializable {
      */
     protected abstract String encodeQueryStringParameterValue(
             String parameterValue);
+
+    /**
+     * Returns the URL pointing to the folder containing frontend files, either
+     * for ES5 (if browser does not support ES6) or ES6 (most browsers).
+     *
+     * @return the absolute or relative URL to the frontend files, ending with a
+     *         slash '/'
+     */
+    protected abstract String getFrontendUrl();
 }
diff --git a/uitest/src/main/java/com/vaadin/tests/resources/FrontendInitialResourceUI.java b/uitest/src/main/java/com/vaadin/tests/resources/FrontendInitialResourceUI.java
new file mode 100644
index 0000000000..cf90591eb8
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/resources/FrontendInitialResourceUI.java
@@ -0,0 +1,35 @@
+/*
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.resources;
+
+import com.vaadin.annotations.JavaScript;
+import com.vaadin.annotations.Widgetset;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUIWithLog;
+
+@JavaScript("frontend://logFilename.js")
+@Widgetset("com.vaadin.DefaultWidgetSet")
+public class FrontendInitialResourceUI extends AbstractTestUIWithLog {
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        getPage().getJavaScript()
+                .execute("document.body.innerHTML=window.jsFile;\n");
+
+    }
+
+}
diff --git a/uitest/src/main/java/com/vaadin/tests/resources/FrontendLaterLoadedResourceUI.java b/uitest/src/main/java/com/vaadin/tests/resources/FrontendLaterLoadedResourceUI.java
new file mode 100644
index 0000000000..6fc1338e28
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/resources/FrontendLaterLoadedResourceUI.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.resources;
+
+import com.vaadin.annotations.JavaScript;
+import com.vaadin.annotations.Widgetset;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUIWithLog;
+import com.vaadin.ui.Button;
+
+@Widgetset("com.vaadin.DefaultWidgetSet")
+public class FrontendLaterLoadedResourceUI extends AbstractTestUIWithLog {
+
+    @JavaScript("frontend://logFilename.js")
+    public static class MyButton extends Button {
+
+    }
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        Button b = new MyButton();
+        b.addClickListener(e -> {
+            getPage().getJavaScript()
+                    .execute("document.body.innerHTML=window.jsFile;\n");
+        });
+        addComponent(b);
+    }
+
+}
diff --git a/uitest/src/main/webapp/VAADIN/frontend/es5/logFilename.js b/uitest/src/main/webapp/VAADIN/frontend/es5/logFilename.js
new file mode 100644
index 0000000000..7dd7eaea60
--- /dev/null
+++ b/uitest/src/main/webapp/VAADIN/frontend/es5/logFilename.js
@@ -0,0 +1 @@
+window.jsFile = "/VAADIN/frontend/es5/logFilename.js";
diff --git a/uitest/src/main/webapp/VAADIN/frontend/es6/logFilename.js b/uitest/src/main/webapp/VAADIN/frontend/es6/logFilename.js
new file mode 100644
index 0000000000..db154ac218
--- /dev/null
+++ b/uitest/src/main/webapp/VAADIN/frontend/es6/logFilename.js
@@ -0,0 +1 @@
+window.jsFile = "/VAADIN/frontend/es6/logFilename.js";
diff --git a/uitest/src/test/java/com/vaadin/tests/resources/FrontendInitialResourceUITest.java b/uitest/src/test/java/com/vaadin/tests/resources/FrontendInitialResourceUITest.java
new file mode 100644
index 0000000000..555e286427
--- /dev/null
+++ b/uitest/src/test/java/com/vaadin/tests/resources/FrontendInitialResourceUITest.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.resources;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.openqa.selenium.By;
+
+import com.vaadin.testbench.parallel.BrowserUtil;
+import com.vaadin.tests.tb3.MultiBrowserTest;
+
+public class FrontendInitialResourceUITest extends MultiBrowserTest {
+
+    @Test
+    public void correctEs5Es6FileImportedThroughFrontend() {
+        openTestURL();
+        String es;
+        if (BrowserUtil.isIE(getDesiredCapabilities())
+                || BrowserUtil.isPhantomJS(getDesiredCapabilities())) {
+            es = "es5";
+        } else {
+            es = "es6";
+        }
+        testBench().disableWaitForVaadin(); // For some reason needed by IE11
+
+        Assert.assertEquals("/VAADIN/frontend/" + es + "/logFilename.js",
+                findElement(By.tagName("body")).getText());
+    }
+
+}
diff --git a/uitest/src/test/java/com/vaadin/tests/resources/FrontendLaterLoadedResourceUITest.java b/uitest/src/test/java/com/vaadin/tests/resources/FrontendLaterLoadedResourceUITest.java
new file mode 100644
index 0000000000..9d8d75b715
--- /dev/null
+++ b/uitest/src/test/java/com/vaadin/tests/resources/FrontendLaterLoadedResourceUITest.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.resources;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.openqa.selenium.By;
+
+import com.vaadin.testbench.elements.ButtonElement;
+import com.vaadin.testbench.parallel.BrowserUtil;
+import com.vaadin.tests.tb3.MultiBrowserTest;
+
+public class FrontendLaterLoadedResourceUITest extends MultiBrowserTest {
+
+    @Test
+    public void correctEs5Es6FileImportedThroughFrontend() {
+        openTestURL();
+        $(ButtonElement.class).first().click();
+        String es;
+        if (BrowserUtil.isIE(getDesiredCapabilities())
+                || BrowserUtil.isPhantomJS(getDesiredCapabilities())) {
+            es = "es5";
+        } else {
+            es = "es6";
+        }
+        testBench().disableWaitForVaadin(); // For some reason needed by IE11
+
+        Assert.assertEquals("/VAADIN/frontend/" + es + "/logFilename.js",
+                findElement(By.tagName("body")).getText());
+    }
+
+}