Add activeElement() helper

jsor · Aug 13, 2018 · 577f469 · 577f469
1 parent 0f7991d
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diff --git a/README.md b/README.md
@@ -45,6 +45,7 @@ import {
     viewportWidth,
 
     // Element
+    activeElement,
     create,
     addClass,
     removeClass,
@@ -74,6 +75,7 @@ API
   * [viewportHeight()](#viewportheight)
   * [viewportWidth()](#viewportwidth)
 * [Element](#element)
+  * [activeElement()](#activeelement)
   * [create()](#create)
   * [addClass()](#addclass)
   * [removeClass()](#removeclass)
@@ -158,6 +160,20 @@ const vpWidth = viewportWidth();
 
 ### Element
 
+#### activeElement()
+
+```
+activeElement(): Element
+```
+
+Returns the element that currently has focus.
+
+##### Example
+
+```javascript
+const element = activeElement();
+```
+
 #### create()
 
 ```

diff --git a/index.js b/index.js
@@ -3,6 +3,7 @@ import scrollbarSize from './src/dimension/scrollbar-size';
 import viewportHeight from './src/dimension/viewport-height';
 import viewportWidth from './src/dimension/viewport-width';
 
+import activeElement from './src/element/active-element';
 import create from './src/element/create';
 import {addClass, hasClass, removeClass} from './src/element/class';
 import data from './src/element/data';
@@ -25,6 +26,7 @@ export {
     viewportWidth,
 
     // Element
+    activeElement,
     create,
     addClass,
     removeClass,

diff --git a/src/element/active-element.js b/src/element/active-element.js
@@ -0,0 +1,14 @@
+/*
+ * Ported from jQuery UI's safeActiveElement()
+ * https://github.com/jquery/jquery-ui/blob/74f8a0ac952f6f45f773312292baef1c26d81300/ui/safe-active-element.js
+ */
+
+export default function activeElement() {
+    try {
+        const {activeElement} = document;
+
+        return activeElement && activeElement.nodeName ? activeElement : document.body;
+    } catch (e) {
+        return document.body;
+    }
+}
diff --git a/test/element/active-element.test.js b/test/element/active-element.test.js
@@ -0,0 +1,21 @@
+import { activeElement } from '../../index';
+
+describe('activeElement()', () => {
+    it('returns the active element', () => {
+        const element = document.createElement('button');
+
+        document.body.appendChild(element);
+
+        element.focus();
+
+        assert.equal(activeElement(), element);
+
+        document.body.removeChild(element);
+    });
+
+    it('always returns active element', () => {
+        document.activeElement && document.activeElement.blur();
+
+        assert.equal(activeElement(), document.body);
+    });
+});