diff --git a/types/franc/index.d.ts b/types/franc/index.d.ts
index 613c46946f..f5d4268db0 100644
--- a/types/franc/index.d.ts
+++ b/types/franc/index.d.ts
@@ -13,6 +13,7 @@ interface Options {
     minLength?: number;
     whitelist?: ISO6393[];
     blacklist?: ISO6393[];
+    only?: string[];
 }
 
 declare function detect(text: string, options?: Options): ISO6393;