> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metabind.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Placeholder

> A bridge to native platform components, resolved by name at runtime from the host app's component registry.

export const PlatformStatuses = ({statuses}) => {
  const StatusBadge = ({status, label}) => {
    const styles = {
      green: {
        backgroundColor: '#dcfce7',
        color: '#166534'
      },
      orange: {
        backgroundColor: '#fed7aa',
        color: '#9a3412'
      },
      red: {
        backgroundColor: '#fecaca',
        color: '#991b1b'
      },
      gray: {
        backgroundColor: '#f3f4f6',
        color: '#4b5563'
      }
    };
    const baseStyle = {
      display: 'inline-flex',
      alignItems: 'center',
      padding: '0.125rem 0.625rem',
      borderRadius: '9999px',
      fontSize: '0.875rem',
      fontWeight: '500'
    };
    const colorStyle = styles[status] || styles.green;
    return <span style={{
      ...baseStyle,
      ...colorStyle
    }}>
        {label || status}
      </span>;
  };
  const STATUS_CONFIG = {
    supported: {
      label: "Supported",
      color: "green"
    },
    partial: {
      label: "Partial",
      color: "orange"
    },
    "not-implemented": {
      label: "Not Implemented",
      color: "gray"
    }
  };
  const renderCard = (platform, value) => {
    if (!value) return null;
    const {status, note} = typeof value === "string" ? {
      status: value
    } : value;
    const config = STATUS_CONFIG[status];
    if (!config) return null;
    const titleMap = {
      ios: "SwiftUI",
      android: "Jetpack Compose",
      web: "Web"
    };
    return <Card key={platform} title={titleMap[platform] || platform}>
          <StatusBadge status={config.color} label={config.label} />
          {note && <div style={{
      marginTop: '0.5rem',
      fontSize: '0.875rem',
      color: '#6b7280'
    }}>
              {note}
            </div>}
      </Card>;
  };
  if (statuses == null) {
    return null;
  }
  return <Columns cols="3">
      {Object.entries(statuses).map(([platform, value]) => renderCard(platform, value))}
    </Columns>;
};

export const ComposeJS = ({code, name, height}) => {
  const encodedCode = useMemo(() => {
    if (!code) return "";
    try {
      return btoa(code);
    } catch (e) {
      console.error("Failed to encode code", e);
      return "";
    }
  }, [code]);
  if (!encodedCode) {
    return null;
  }
  return <iframe src={`https://www.metabind.ai/embed?code=${encodedCode}&name=${name ?? 'Example'}`} loading="lazy" style={{
    width: "100%",
    height: height || '350px',
    border: "1px solid #e5e7eb",
    borderRadius: "var(--rounded-2xl,1rem)",
    overflow: "hidden"
  }} title="ComposeJS Preview" />;
};

```typescript theme={null}
Placeholder(props: PlaceholderProps, children: Component[]): Component;
```

```typescript theme={null}
type PlaceholderProps = {
    name?: string;
    props?: Record<string, any>;
    title?: string;
    validPlatforms?: Platform[];
};
```

<ParamField path="name" type="string" optional>
  Name used to resolve the native component from the host app's component registry.
</ParamField>

<ParamField path="props" type="Record<string, any>" optional>
  Props passed through to the native component.
</ParamField>

<ParamField path="title" type="string" optional>
  Display title shown in the web preview.
</ParamField>

<ParamField path="validPlatforms" type="Platform[]" optional>
  Platforms where the native component is available. Options: `"iOS"`, `"macOS"`, `"watchOS"`, `"tvOS"`, `"visionOS"`, `"web"`, `"android"`.
</ParamField>

<ParamField path="children" type="Component[]" required>
  Fallback content displayed when the native component is not registered or not available on the current platform.
</ParamField>

## Support

<PlatformStatuses
  statuses={{
ios: { status: "supported" },
android: "not-implemented",
web: { status: "supported" },
}}
/>

## Usage

### Basic placeholder with fallback

```typescript theme={null}
Placeholder(
    { name: "MapView", props: { latitude: 37.7749 } },
    [Text("Map not available")]
)
```

### Platform-specific component

```typescript theme={null}
Placeholder(
    {
        name: "ARView",
        title: "AR View",
        validPlatforms: ["iOS", "visionOS"]
    },
    [
        VStack([
            Image({ systemName: "arkit" }),
            Text("AR is available on iOS and visionOS only")
                .font("caption")
        ])
    ]
)
```

### With passed props

```typescript theme={null}
Placeholder(
    {
        name: "NativeVideoPlayer",
        props: { url: "https://example.com/video.mp4", autoplay: true },
        title: "Video Player"
    },
    [Text("Video playback not available")]
)
```

## Notes

* The host app registers native views by name. At runtime, if a component matching `name` is found in the registry, it renders natively. Otherwise, the `children` are displayed as fallback.
* On the web preview in the Composer, the `title` is displayed to identify the placeholder.

## See Also

* [Image](/bindjs/components/Image) -- image display
* [Video](/bindjs/components/Video) -- video playback