diff --git a/packages/firestore/test/util/node_persistence.ts b/packages/firestore/test/util/node_persistence.ts
index 6324221872..90977b0295 100644
--- a/packages/firestore/test/util/node_persistence.ts
+++ b/packages/firestore/test/util/node_persistence.ts
@@ -16,6 +16,7 @@
  */
 
 import * as fs from 'fs';
+// @ts-ignore: There are no types for indexeddbshim.
 import * as registerIndexedDBShim from 'indexeddbshim';
 import * as os from 'os';