diff --git a/dagre-d3/dagre-d3-tests.ts b/dagre-d3/dagre-d3-tests.ts
index 2ba8675436..ef5fddffac 100644
--- a/dagre-d3/dagre-d3-tests.ts
+++ b/dagre-d3/dagre-d3-tests.ts
@@ -14,5 +14,6 @@ namespace DagreD3Tests {
 
     const render = new dagreD3.render();
     const svg = d3.select("svg");
+    render.arrows()["arrowType"] = (parent: JQuery, id: string, edge: Dagre.Edge, type: string) => {};
     render(svg, graph);
 }
diff --git a/dagre-d3/dagre-d3.d.ts b/dagre-d3/dagre-d3.d.ts
index 0bc71294c8..68e24c2fa5 100644
--- a/dagre-d3/dagre-d3.d.ts
+++ b/dagre-d3/dagre-d3.d.ts
@@ -5,6 +5,7 @@
 
 /// <reference path="../d3/d3.d.ts"/>
 /// <reference path="../dagre/dagre.d.ts"/>
+/// <reference path="../jquery/jquery.d.ts" />
 
 declare namespace Dagre {
 
@@ -23,6 +24,8 @@ declare namespace Dagre {
     }
 
     interface Render {
+        // see http://cpettitt.github.io/project/dagre-d3/latest/demo/user-defined.html for example usage
+        arrows (): { [arrowStyleName: string]: (parent: JQuery, id: string, edge: Dagre.Edge, type: string) => void };
         new (): Render;
         (selection: d3.Selection<any>, g: Dagre.Graph): void;
     }