# CesiumIonAuth

class in `3d-tiles-renderer/core/plugins`

```js
import { CesiumIonAuth } from '3d-tiles-renderer/core/plugins';
```

Authentication helper for Cesium Ion. Fetches and caches a bearer token from the
Cesium Ion endpoint and injects it into outgoing requests. Supports optional
automatic token refresh on 4xx responses.

## Constructor

```js
new CesiumIonAuth( options?: Object )
```

- `options`, `Object`, optional, default `{}`
  - `apiToken`, `string`
  - `autoRefreshToken`, `boolean`, optional, default `false`

## Properties

### .apiToken: string

The Cesium Ion access token.

### .autoRefreshToken: boolean

Whether to automatically refresh the token on 4xx errors.

### .authURL: string | null

The endpoint URL used to fetch the bearer token.