diff --git a/d3/d3.d.ts b/d3/d3.d.ts
index 0c0be2178..d10935770 100644
--- a/d3/d3.d.ts
+++ b/d3/d3.d.ts
@@ -2635,6 +2635,7 @@ declare module D3 {
                 (): any[];
             };
             copy(): QuantizeScale;
+            invertExtent(y: any): any[];
         }
 
         export interface ThresholdScale extends Scale {