jQuery: The interface used to specify easing functions add

jquery/jquery.d.ts

@@ -348,6 +348,13 @@ interface JQueryEventConstructor {
     new (name: string, eventProperties?: any): JQueryEventObject;
 }
 
+/**
+ * The interface used to specify easing functions.
+ */
+interface JQueryEasing {
+    linear(p: number): number;
+    swing(p: number): number;
+}
 
 /*
     Static members of jQuery (those on $ and jQuery themselves)
@@ -647,6 +654,7 @@ interface JQueryStatic {
 
     Animation(elem: any, properties: any, options: any): any;
 
+    easing: JQueryEasing;
 }
 
 /*