diff --git a/src/types.ts b/src/types.ts
index 8d030195..220b8512 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -103,7 +103,7 @@ export interface IAceOptions {
   tooltipFollowsMouse?: boolean;
   firstLineNumber?: number;
   overwrite?: boolean;
-  newLineMode?: boolean;
+  newLineMode?: "auto" | "unix" | "windows";
   useWorker?: boolean;
   useSoftTabs?: boolean;
   tabSize?: number;