# useAppShell

```tsx
import { useAppShell } from '@akinon/app-shell';

const ShellComponent = () => {
  const { apps, configs, navigate } = useAppShell();

  return (
    <div>
      <h1>Registered Apps: {apps.length}</h1>
      <button onClick={() => navigate({ path: '/dashboard' })}>
        Go to Dashboard
      </button>
    </div>
  );
};
```

### <mark style="color:red;">Return Value</mark>

The `useAppShell` hook returns an `AppShellContextState` object:

<table><thead><tr><th width="150.45703125">Property</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td><code>apps</code></td><td><code>RegisteredApp[]</code></td><td>List of registered micro-frontend applications</td></tr><tr><td><code>configs</code></td><td><code>Map&#x3C;number | UUID, ApplicationConfig></code></td><td>Configuration for each registered app</td></tr><tr><td><code>navigate</code></td><td><code>(payload: NavigationPayload) => void</code></td><td>Navigation function</td></tr><tr><td><code>frames</code></td><td><code>MutableRefObject&#x3C;Map&#x3C;number | UUID, HTMLIFrameElement>></code></td><td>References to iframe elements</td></tr><tr><td><code>buses</code></td><td><code>MutableRefObject&#x3C;Map&#x3C;number | UUID, Framebus>></code></td><td>Framebus instances for communication</td></tr><tr><td><code>instances</code></td><td><code>Map&#x3C;number | UUID, AppInstanceInfo></code></td><td>App instances by ID</td></tr><tr><td><code>modals</code></td><td><code>Map&#x3C;UUID, number | UUID></code></td><td>UUID values for rich modals</td></tr><tr><td><code>modalContext</code></td><td><code>Map&#x3C;UUID, unknown></code></td><td>Context data for modals</td></tr></tbody></table>

### <mark style="color:red;">AppShellContextState Type</mark>

```typescript
interface AppShellContextState {
  apps: RegisteredApp[];
  configs: Map<number | UUID, PluginApplicationConfig | FullpageApplicationConfig>;
  navigate: (payload: ApplicationNavigationPayload) => void;
  frames?: React.MutableRefObject<Map<number | UUID, HTMLIFrameElement>>;
  buses?: React.MutableRefObject<Map<number | UUID, Framebus>>;
  instances: Map<number | UUID, AppInstanceInfo>;
  modals?: Map<UUID, number | UUID>;
  modalContext?: Map<UUID, unknown>;
}

interface AppInstanceInfo {
  id: number | UUID;
  basePath: string;
  config: FullpageApplicationConfig | PluginApplicationConfig;
  iframe: HTMLIFrameElement;
  bus: Framebus;
}
```

### <mark style="color:red;">Usage Examples</mark>

#### Accessing Registered Apps

```tsx
const AppList = () => {
  const { apps } = useAppShell();

  return (
    <ul>
      {apps.map(app => (
        <li key={app.pk}>
          {app.name} - {app.config.visible_type}
        </li>
      ))}
    </ul>
  );
};
```

#### Programmatic Navigation

```tsx
const NavigationButtons = () => {
  const { navigate } = useAppShell();

  return (
    <div>
      <button onClick={() => navigate({ path: '/orders' })}>Orders</button>
      <button onClick={() => navigate({ path: '/products' })}>Products</button>
      <button onClick={() => navigate({ path: '/settings', id: 1 })}>
        Settings (App 1)
      </button>
    </div>
  );
};
```

#### Accessing App Configurations

```tsx
const AppInfo = ({ appId }: { appId: number }) => {
  const { configs } = useAppShell();
  const config = configs.get(appId);

  if (!config) return <p>App not found</p>;

  return (
    <div>
      <p>URL: {config.web_url}</p>
      <p>Type: {config.visible_type}</p>
    </div>
  );
};
```

#### Working with Iframe References

```tsx
const IframeManager = () => {
  const { frames } = useAppShell();

  const reloadApp = (appId: number) => {
    const iframe = frames?.current.get(appId);
    if (iframe) {
      iframe.contentWindow?.location.reload();
    }
  };

  return (
    <button onClick={() => reloadApp(1)}>
      Reload App 1
    </button>
  );
};
```

#### Sending Messages via Framebus

```tsx
const MessageSender = () => {
  const { buses } = useAppShell();

  const sendMessage = (appId: number, event: string, data: any) => {
    const bus = buses?.current.get(appId);
    if (bus) {
      bus.emit(event, data);
    }
  };

  return (
    <button onClick={() => sendMessage(1, 'custom-event', { foo: 'bar' })}>
      Send Custom Message
    </button>
  );
};
```

### <mark style="color:red;">Best Practices</mark>

#### 1. Use at the Right Level

Call `useAppShell` in components that need shell context, not at the top level:

```tsx
// ✅ Good - Use where needed
const AppRenderer = ({ id }) => {
  const { frames } = useAppShell();
  // ...
};

// ❌ Avoid - Don't destructure everything at top level
const App = () => {
  const shellContext = useAppShell(); // Then pass to children
};
```

#### 2. Check for Optional Values

Some properties are optional and may be undefined:

```tsx
const Component = () => {
  const { frames, buses } = useAppShell();

  const sendMessage = (appId: number) => {
    const bus = buses?.current.get(appId);
    if (!bus) {
      console.warn('Framebus not available for app:', appId);
      return;
    }
    bus.emit('event', data);
  };
};
```

#### 3. Memoize Derived Values

When computing values from the context, memoize them:

```tsx
const ActiveApps = () => {
  const { apps } = useAppShell();

  const activeApps = useMemo(
    () => apps.filter(app => app.is_active && app.is_visible),
    [apps]
  );

  return <AppList apps={activeApps} />;
};
```

### <mark style="color:red;">Related</mark>

* [Components](/akinon-ui/ui-protocol/shell-application/components.md) - AppRenderer, PluginRenderer, ModalRenderer
* [API Reference](/akinon-ui/ui-protocol/shell-application/api-reference.md) - Complete type definitions


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