diff --git a/src/index.ts b/src/index.ts
index 9df5a04..b17dd59 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -10,7 +10,7 @@ import { QueryComplexityOptions } from './QueryComplexity';
 export * from './estimators';
 export * from './QueryComplexity';
 
-export default function createQueryComplexityValidator(options: QueryComplexityOptions): Function {
+export default function createQueryComplexityValidator(options: QueryComplexityOptions): (context: ValidationContext) => QueryComplexity {
   return (context: ValidationContext): QueryComplexity => {
     return new QueryComplexity(context, options);
   };