diff --git a/jquery.gridster/gridster-tests.ts b/jquery.gridster/gridster-tests.ts
index 72c90a6f0..80c71e535 100644
--- a/jquery.gridster/gridster-tests.ts
+++ b/jquery.gridster/gridster-tests.ts
@@ -16,7 +16,7 @@ var options: GridsterOptions = {
 	}
 };
 
-var gridster = <Gridster>$('.gridster ul').gridster(options).data('grister');
+let gridster: Gridster = $('.gridster ul').gridster(options).data('gridster');
 gridster.add_widget('<li class="new">The HTML of the widget...</li>', 2, 1);
 gridster.remove_widget($('gridster li').eq(3).get(0));
 var json = gridster.serialize<SerializeData>();
diff --git a/jquery.gridster/gridster.d.ts b/jquery.gridster/gridster.d.ts
index e003f0ebc..abbb4c8e0 100644
--- a/jquery.gridster/gridster.d.ts
+++ b/jquery.gridster/gridster.d.ts
@@ -248,3 +248,7 @@ interface Gridster {
 	**/
 	disable(): Gridster;
 }
+
+interface JQuery {
+    data(key: "gridster"): Gridster;
+}
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