diff --git a/source/runner/runners/utils/transpiler.ts b/source/runner/runners/utils/transpiler.ts
index 24dbf4a61..d84670e74 100644
--- a/source/runner/runners/utils/transpiler.ts
+++ b/source/runner/runners/utils/transpiler.ts
@@ -87,8 +87,8 @@ export const babelify = (content: string, filename: string, extraPlugins: string
     filename,
     filenameRelative: filename,
     sourceMap: false,
-    sourceFileName: null,
-    sourceMapTarget: null,
+    sourceFileName: undefined,
+    sourceMapTarget: undefined,
     sourceType: "module",
     plugins: [...extraPlugins, ...options.plugins],
   }