diff --git a/projects/core/src/lib/types/mask.ts b/projects/core/src/lib/types/mask.ts
index 4a9c74a23..52c60c923 100644
--- a/projects/core/src/lib/types/mask.ts
+++ b/projects/core/src/lib/types/mask.ts
@@ -1,6 +1,6 @@
 import type {ElementState} from './element-state';
 
-export type MaskitoMaskExpression = Array<RegExp | string> | RegExp;
+export type MaskitoMaskExpression = ReadonlyArray<RegExp | string> | RegExp;
 
 export type MaskitoMask =
     | MaskitoMaskExpression