diff --git a/.gitignore b/.gitignore
index 064213f..87ebeb4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,7 @@
 node_modules
 dist
 /.nyc_output
-.DS_Store
\ No newline at end of file
+.DS_Store
+
+# ide
+.idea/
diff --git a/src/index.d.ts b/src/index.d.ts
index 5d0b749..c7af358 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -2,6 +2,8 @@ export const FS: {
     writeFile: (fileName: string, binaryData: Uint8Array) => void,
     readFile: (fileName: string) => Uint8Array,
     unlink: (fileName: string) => void,
+    mkdir: (fileName: string) => void,
+    readdir: (fileName: string) => string[],
 }
 
 type FSMethodNames = { [K in keyof typeof FS]: (typeof FS)[K] extends (...args: any[]) => any ? K : never }[keyof typeof FS];