Workaround Edge 15's broken CSS Custom Properties

Fixes #111
webcomponents · Aug 8, 2017 · 74577b1 · 74577b1
1 parent 930c752
commit 74577b1
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Showing 9 changed files with 69 additions and 8 deletions.
diff --git a/apply-shim.min.js b/apply-shim.min.js
diff --git a/apply-shim.min.js.map b/apply-shim.min.js.map
diff --git a/custom-style-interface.min.js b/custom-style-interface.min.js
diff --git a/custom-style-interface.min.js.map b/custom-style-interface.min.js.map
diff --git a/scoping-shim.min.js b/scoping-shim.min.js
diff --git a/scoping-shim.min.js.map b/scoping-shim.min.js.map
diff --git a/src/style-settings.js b/src/style-settings.js
@@ -24,7 +24,9 @@ function calcCssVariables(settings) {
     // safari 9.1 has a recalc bug: https://bugs.webkit.org/show_bug.cgi?id=155782
     // However, shim css custom properties are only supported with ShadyDOM enabled,
     // so fall back on native if we do not detect ShadyDOM
-    nativeCssVariables = nativeShadow || Boolean(!navigator.userAgent.match('AppleWebKit/601') &&
+    // Edge 15: custom properties used in ::before and ::after will also be used in the parent element
+    // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/12414257/
+    nativeCssVariables = nativeShadow || Boolean(!navigator.userAgent.match(/AppleWebKit\/601|Edge\/15/) &&
       window.CSS && CSS.supports && CSS.supports('box-shadow', '0 0 0 var(--foo)'));
   }
 }

diff --git a/tests/runner.html b/tests/runner.html
@@ -29,7 +29,8 @@
     'complicated-mixin-ordering.html',
     'dynamic-scoping.html',
     'settings.html',
-    'chrome-devtools.html'
+    'chrome-devtools.html',
+    'workarounds.html'
   ];
   // http://eddmann.com/posts/cartesian-product-in-javascript/
   function flatten(arr) { return [].concat.apply([], arr) }

diff --git a/tests/workarounds.html b/tests/workarounds.html
@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<!--
+@license
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+<html>
+
+<head>
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
+  <meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1, user-scalable=yes">
+  <script>
+    WCT = { waitFor: function (cb) { HTMLImports.whenReady(cb) } }
+  </script>
+  <script src="./test-flags.js"></script>
+  <script src="../../web-component-tester/browser.js"></script>
+  <script src="../../webcomponents-platform/webcomponents-platform.js"></script>
+  <script src="../../es6-promise/dist/es6-promise.auto.min.js"></script>
+  <script src="../../template/template.js"></script>
+  <script src="../../html-imports/html-imports.min.js"></script>
+  <script src="../../shadydom/shadydom.min.js"></script>
+  <script src="../../custom-elements/custom-elements.min.js"></script>
+  <script src="../scoping-shim.min.js"></script>
+  <script src="../apply-shim.min.js"></script>
+  <script src="../custom-style-interface.min.js"></script>
+  <script src="module/generated/make-element.js"></script>
+</head>
+<body>
+  <template id="x-bug">
+    <style>
+      :host {
+        --bg: rgb(255, 0, 0);
+      }
+      div::after {
+        content: 'test';
+        background-color: var(--bg);
+      }
+    </style>
+    <div></div>
+  </template>
+  <script>
+    suite('Workarounds', function() {
+      test('Edge 15', function() {
+        makeElement('x-bug');
+        let el = document.createElement('x-bug');
+        document.body.appendChild(el);
+        let div = el.shadowRoot.querySelector('div');
+        assert.notEqual(getComputedStyle(div).getPropertyValue('background-color').trim(), 'rgb(255, 0, 0)');
+      })
+    });
+  </script>
+</body>
+</html>