Using QScreen in JavaScript

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QScreen>
#include <QDebug>

int main(int argc, char *argv[])
{
#if defined(Q_OS_WIN)
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
#endif

    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;

    QScreen *firstScreen = app.screens().first();
    engine.globalObject().setProperty("firstScreen", engine.newQObject(firstScreen));

    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

main.qml

import QtQuick 2.9
import QtQuick.Controls 2.2

import "test.js" as Test

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Component.onCompleted: Test.func()
}

test.js

function func() {
    print(firstScreen.availableVirtualGeometry)
}