Add a element decorator to handle creating custom elements

lib/decorators/element.js

@@ -0,0 +1,44 @@
+'use babel'
+
+import {registerOrUpdateElement} from 'atom-utils'
+
+/**
+ * Generates a decorator function to convert a class into a custom element
+ * through the `registerOrUpdateElement` method from `atom-utils`.
+ *
+ * The decorator will take care to return the generated element class so that
+ * you can just export it directly as demonstrated below.
+ *
+ * As supported by the `registerOrUpdateElement` method, static member will
+ * be available on the new class.
+ *
+ * **Note: As there's some limitations when modifying the prototype
+ * of a custom element, if you need to inject element callbacks (like
+ * `createdCallback`) through a mixin, the mixins should be included before
+ * converting the class as a custom element. You'll be able to achieve that by
+ * placing the `include` decorator after the `element` one as shown in the
+ * second example.**
+ *
+ * @param  {string} elementName the node name of the element to register
+ * @return {Function} the element class as returned by
+ *                    `document.registerElement`
+ * @example
+ * @element('dummy-element-name')
+ * export default class SomeClass {
+ *   // ...
+ * }
+ *
+ * @element('dummy-element-with-mixin')
+ * @include(SomeMixin)
+ * export default class SomeClass {
+ *   // ...
+ * }
+ */
+export default function element (elementName) {
+  return function (cls) {
+    let elementClass = registerOrUpdateElement(elementName, {
+      class: cls
+    })
+    return elementClass
+  }
+}