Move version to ElementMixin prototype

lib/mixins/element-mixin.js

@@ -17,6 +17,12 @@ import { DomModule } from '../elements/dom-module.js';
 import { PropertyEffects } from './property-effects.js';
 import { PropertiesMixin } from './properties-mixin.js';
 
+/**
+ * Current Polymer version in Semver notation.
+ * @type {string} Semver notation of the current version of Polymer.
+ */
+export const version = '3.0.5';
+
 /**
  * Element class mixin that provides the core API for Polymer's meta-programming
  * features including template stamping, data-binding, attribute deserialization,
@@ -278,6 +284,14 @@ export const ElementMixin = dedupingMixin(base => {
    */
   class PolymerElement extends polymerElementBase {
 
+    /**
+     * Current Polymer version in Semver notation.
+     * @type {string} Semver notation of the current version of Polymer.
+     */
+    static get polymerElementVersion() {
+      return version;
+    }
+
     /**
      * Override of PropertiesMixin _finalizeClass to create observers and
      * find the template.

polymer-element.js

@@ -9,6 +9,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 */
 
 import { ElementMixin } from './lib/mixins/element-mixin.js';
+export { version } from './lib/mixins/element-mixin.js';
 export { html } from './lib/utils/html-tag.js';
 
 /**
@@ -27,9 +28,3 @@ export { html } from './lib/utils/html-tag.js';
  *   attribute deserialization, and property change observation
  */
 export const PolymerElement = ElementMixin(HTMLElement);
-
-/**
- * Current Polymer version in Semver notation.
- * @type {String} Semver notation of the current version of Polymer.
- */
-export const version = '3.0.5';

test/unit/polymer.element.html

@@ -397,6 +397,9 @@ <h1>Sub template</h1>
     assert.equal(fixtureEl.getAttribute('prop'), 'propValue');
   });
 
+  test('version', function() {
+    assert.isOk(el.constructor.polymerElementVersion);
+  });
 });
 
 suite('subclass', function() {