プロバイダを切り替える

@StateObject private var googleState = GoogleMapViewState(cameraPosition: initial)
@StateObject private var mapLibreState = MapLibreViewState(cameraPosition: initial)

// 共通インターフェース越しならカメラ操作は分岐なしで書ける
private var activeState: any MapViewStateProtocol {
    provider == .googleMaps ? googleState : mapLibreState
}

@ViewBuilder
private var mapView: some View {
    switch provider {
    case .googleMaps:
        GoogleMapView(state: googleState, sdkInitialize: {
            GMSServices.provideAPIKey(apiKey)
        }) { Marker(state: markerState) }
    case .mapLibre:
        MapLibreMapView(state: mapLibreState) { Marker(state: markerState) }
    }
}

// フックはコンポーネントごとに固定で呼ぶ。ビューだけを差し替える
const maplibre = useMapLibreViewState({ id: 'maplibre', cameraPosition: INIT });
const google = useGoogleMapViewState({ id: 'google', cameraPosition: INIT });

switch (provider) {
  case 'maplibre':
    return <MapLibreMapView2D state={maplibre}>{children}</MapLibreMapView2D>;
  case 'google-maps':
    return <GoogleMapView2D state={google}>{children}</GoogleMapView2D>;
}