diff --git a/sdk/storage/storage-file-share/src/utils/utils.node.ts b/sdk/storage/storage-file-share/src/utils/utils.node.ts
index b773afe82221..547cca0fbcc4 100644
--- a/sdk/storage/storage-file-share/src/utils/utils.node.ts
+++ b/sdk/storage/storage-file-share/src/utils/utils.node.ts
@@ -18,7 +18,7 @@ export async function streamToBuffer(
   buffer: Buffer,
   offset: number,
   end: number,
-  encoding?: string
+  encoding?: BufferEncoding
 ): Promise<void> {
   let pos = 0; // Position in stream
   const count = end - offset; // Total amount of data needed in stream