You could also wrap whatever you want to push in a Component like this
Component {
id: one
MyFirstView { }
}
Component {
id: two
MySecondView { }
}
StackView {
id: stackView
initialItem: one
}
This way your views will be created once you push them.
You can also push an URL
stackView.push("MySecondView.qml")
And you can pass properties too
stackView.push({ item: two, properties: { color: "#3498db" }})