| --- | |
| title: 'Circular structure in `getInitialProps` result' | |
| --- | |
| ## Why This Error Occurred | |
| `getInitialProps` is serialized to JSON using `JSON.stringify` and sent to the client side for hydrating the page. | |
| However, the result returned from `getInitialProps` can't be serialized when it has a circular structure. | |
| ## Possible Ways to Fix It | |
| Circular structures are not supported, so the way to fix this error is removing the circular structure from the object that is returned from `getInitialProps`. | |
| For example, the `req` instance exposed is a circular object and can not be serialized, instead the specific fields such as relevant headers on the instance should be passed specifically. | |