the case of the missing file

src/express/middleware/createAuthHeaderFromCookie.js

@@ -0,0 +1,14 @@
+const createAuthHeaderFromCookie = (req, _, next) => {
+  if (process.env.NODE_ENV !== 'production' || this.config.productionGraphQLPlayground) {
+    const existingAuthHeader = req.get('Authorization');
+    const { token } = req.cookies;
+
+    if (!existingAuthHeader && token) {
+      req.headers.authorization = `JWT ${token}`;
+    }
+  }
+
+  next();
+};
+
+module.exports = createAuthHeaderFromCookie;