CalendarModel.qml

import QtQuick 2.14
import QtQml.Models 2.14

import "util.js" as UTIL

Item
{
    id: control
    property alias model: private_props.model
    property date from: new Date (1950, 1, 1)
    property date to: new Date (2050, 12, 1)

    Component.onCompleted:
    {
        init();
    }

    function index_of(year, month)
    {
        return UTIL.find_in_model(private_props.model, (item) => {
                                      return (item.year === year && item.month === month);
                                  });
    }

    QtObject
    {
        id: private_props
        property ListModel model: ListModel {}
    }

    function init()
    {
        if (!(from) || !(to) || (from > to))
            return;

        private_props.model.clear();
        const start_year  = from.getFullYear();
        const end_year    = to.getFullYear();


        for (let year = start_year; year <= end_year; year++)
        {
            const end_month = (year === end_year) ?  to.getMonth() : 12;
            const start_month = (year === start_year) ? from.getMonth() : 1;
            for (let month = start_month; month <= end_month; month++)
            {
                private_props.model.append({
                                               year: year,
                                               month: month
                                           });
            }
        }
    }
}