diff --git a/index.d.ts b/index.d.ts
index 4d646ada..567b8dbc 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -172,7 +172,7 @@ declare namespace JSZip {
 
     interface JSZipMetadata {
         percent: number;
-        currentFile: string;
+        currentFile: string | null;
     }
 
     type DataEventCallback<T> = (dataChunk: T, metadata: JSZipMetadata) => void