# TypeScript compatibility

Handle optional response fields accurately when upgrading the SDK.

The SDK generates its public declarations from the TypeScript implementation.
JavaScript entrypoints and returned values are unchanged. Nine response types
now describe values the runtime already returned; strict TypeScript consumers
may need to check for missing fields:

```typescript
import { VolcanoClient } from '@volcano.dev/sdk';

const volcano = new VolcanoClient({ anonKey: 'your-anon-key' });
const { user, error } = await volcano.auth.getUser();
if (error) throw error;
if (user?.created_at !== undefined) {
  console.log(new Date(user.created_at));
}
```

| Response type          | Corrected fields                                                                                                                           |
| ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
| `User`                 | `created_at` and `updated_at` are optional. `status` remains optional.                                                                     |
| `Session`              | `refresh_token` can be `undefined` for HttpOnly cookie sessions.                                                                           |
| `SessionsResponse`     | `sessions`, `total`, `page`, `limit`, and `total_pages` can be `undefined` when omitted by the server.                                     |
| `AuthSession`          | `created_at` and `updated_at` are optional.                                                                                                |
| `OAuthProvider`        | `provider`, `linked_at`, and `updated_at` are optional. Returned provider names are strings; OAuth input names retain their existing enum. |
| `LinkProviderResponse` | `authorization_url` is optional.                                                                                                           |
| `OAuthTokenResponse`   | `message`, `provider`, and `expiresIn` can be `undefined`, in addition to their existing nullable types.                                   |
| `StorageObject`        | `created_at` and `updated_at` are optional; `owner_id` can also be `null`.                                                                 |
| `EmailChangeResponse`  | `emailChangeToken` can be explicitly `undefined`, including with `exactOptionalPropertyTypes`.                                             |

Check the fields your application needs before using them. Error responses keep
their existing `null` values; missing successful fields are not replaced with
invented defaults. Public method arguments, generic parameters, aliases, and
package entrypoints retain their existing signatures.