Property binding doesn't work as expected - qml

Question

I'm trying just now to implement a list with complicated data. In my case it should be an array like this:
[
{ item: "itemName1", objects: [x1,x1,x1] },
{ item: "itemName2", objects: [x2,x2,x2] }
]
As I know there are 2 ways to do that. First of them is to expose QObjectList-based model from C++ to QML. Than currently not interested for me since I want to implement that in pure QML. But ListElement's roles must contain only simple constants, line strings, numbers etc. i.e. no arrays.
So I did the data source as external array:
import QtQuick 2.5
import QtQuick.Layouts 1.2
import QtQuick.Window 2.0
Window {
width: 500
height: 500
id: window
ListView {
id: listView
anchors.fill: parent
anchors.margins: 2
spacing: 2
property var data: [ { name: "item1", objects: [1,2,3]} ]
model: data.length
delegate: Rectangle {
width: parent.width
height: content.height
property int itemIndex: index
color: index % 2 ? "#EFEFEF" : "#DEDEDE"
RowLayout {
id: content
spacing: 10
Text {
text: listView.data[itemIndex].name
}
Column {
Repeater {
model: listView.data[itemIndex].objects.length
Text {
text: listView.data[itemIndex].objects[index]
}
}
}
}
}
Component.onCompleted: {
listView.data.push( { name: "item2", objects: [4,5,6] } );
listView.data.push( { name: "item3", objects: [7,8,9] } );
listView.model = listView.data.length; // it doesnt't work without this line
}
}
}
It works fine with static array. The problem appears when I fill the array dynamically. In this case the property binding (model: data.length) suddenly stops working. So the workaround is to set it manually but I don't like this solution.