diff --git a/src/types/helper.ts b/src/types/helper.ts
index 142b4d8..e20fbd1 100644
--- a/src/types/helper.ts
+++ b/src/types/helper.ts
@@ -5,3 +5,9 @@ export type NoneBinary<T extends string, _T = T> = T extends `${"1" | "0"}${infe
   : never
 
 export type isBinaryString<T extends string> = NoneBinary<T> extends never ? never : T
+
+export type Binary<
+  T extends number,
+  R extends string = "",
+  Arr extends string[] = []
+> = Arr["length"] extends T ? R : Binary<T, `${R}${"0" | "1"}`, [...Arr, ""]>
diff --git a/src/types/index.ts b/src/types/index.ts
index 46fbe21..46a031a 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -1,4 +1,4 @@
-import { isBinaryString } from "./helper"
+import { Binary, isBinaryString } from "./helper"
 
 export type BinaryString<T extends BrickStruct> = {
   [K in keyof T]: isBinaryString<T[K]>
@@ -6,12 +6,6 @@ export type BinaryString<T extends BrickStruct> = {
 
 // type a = BinaryString<("00" | "10" | "01" | "11")[]>
 
-export type Binary<
-  T extends number,
-  R extends string = "",
-  Arr extends string[] = []
-> = Arr["length"] extends T ? R : Binary<T, `${R}${"0" | "1"}`, [...Arr, ""]>
-
 export type Struct<
   T extends number,
   R extends any[] = []