nextauthjs · ThangHuuVu · May 18, 2025 · May 9, 2025 · May 12, 2025 · May 12, 2025
@@ -144,5 +144,8 @@ export function parseActionAndProviderId(
   )
     throw new UnknownAction(`Cannot parse action at ${pathname}`)
 
-  return { action, providerId }
+  return { 
+    action, 
+    providerId: providerId == "undefined" ? undefined : providerId 
+  }
 }
diff --git a/packages/core/test/url-parsing.test.ts b/packages/core/test/url-parsing.test.ts
@@ -70,6 +70,12 @@ describe("parse the action and provider id", () => {
       providerId: "auth0",
       basePath: "/auth",
     },
+    {
+      path: "/auth/signin/undefined",
+      action: "signin",
+      providerId: undefined,
+      basePath: "/auth",
+    },
   ])("$path", ({ path, error, basePath, action, providerId }) => {
     if (action || providerId) {
       const parsed = parseActionAndProviderId(path, basePath)