#1514: Add conditional for rootEl

scripts/test.js

@@ -10,7 +10,7 @@ createTestCafe().then((tc) => {
 	runner = tc.createRunner();
 	return runner
 		.src('./tests/Sortable.test.js')
-		.browsers('chrome')
+		.browsers('chrome:headless')
 		.concurrency(3)
 		.run();
 }).then((actualFailedCount) => {

src/EventDispatcher.js

@@ -11,7 +11,9 @@ export default function dispatchEvent(
 		originalEvent, putSortable, eventOptions
 	}
 ) {
-	sortable = (sortable || rootEl[expando]);
+	sortable = (sortable || (rootEl && rootEl[expando]));
+	if (!sortable) return;
+
 	let evt,
 		options = sortable.options,
 		onName = 'on' + name.charAt(0).toUpperCase() + name.substr(1);