diff --git a/src/services/inventoryService.ts b/src/services/inventoryService.ts
index 46c7c9ee..72462850 100644
--- a/src/services/inventoryService.ts
+++ b/src/services/inventoryService.ts
@@ -333,7 +333,7 @@ export const addItem = async (
     premiumPurchase: boolean = false,
     seed?: bigint,
     targetFingerprint?: string,
-    exactQuantity = false
+    exactQuantity: boolean = false
 ): Promise<IInventoryChanges> => {
     // Bundles are technically StoreItems but a) they don't have a normal counterpart, and b) they are used in non-StoreItem contexts, e.g. email attachments.
     if (typeName in ExportBundles) {