Loader - propery alias on loaded components

I would like to load a Map component in background with a Loader only when the visible Map property is true. Moreover, I need to access the Map center property. How can create a property alias to the Map center property when the Map is loaded with a Loader?

Map2.qml:

Code:

import QtQuick 2.0
import QtQuick.Controls 1.3
import QtLocation 5.5
import QtPositioning 5.3
 
Item {
    id: root
 
    property alias center: ?????
 
    Loader {
        anchors.fill: parent
        id: mapLoader
        active: root.visible
        sourceComponent: cMap
    }
    Component {
        id: cMap
        Item {
            anchors.fill: parent
            Slider {
                id: zoomSlider;
                z: map.z + 3
                minimumValue: map.minimumZoomLevel;
                maximumValue: map.maximumZoomLevel;
                anchors.margins: 10
                anchors.bottom: parent.bottom
                anchors.top: parent.top
                anchors.right: parent.right
                orientation : Qt.Vertical
                value: map.zoomLevel
                onValueChanged: {
                    map.zoomLevel = value
                }
            }
            Map {
                id: map
                anchors.fill: parent
                plugin: osmPlugin
                zoomLevel: 7
            }
            Plugin {
                id: osmPlugin
                name: "osm"
            }
 
        }
    }
}

Using on another qml:
...

Code:

Map2 {
     visible: cbMap.checked
     center: QtPositioning.coordinate(1.759767, 1.864124)
}

...