diff --git a/src/TileSource.js b/src/TileSource.js
index 47a3805..9430489 100644
--- a/src/TileSource.js
+++ b/src/TileSource.js
@@ -169,6 +169,7 @@ class TileSource {
       return true;
     } catch (error) {
       return error.code === 'EEXIST';
+      throw error;
     }
   }
 }