[Interest] QML: Considerations on an interesting design pattern that relies on JS engine's garbage collection

[Fatih Uzunoğlu]

 > However, if you create a new Component object in every
 > derived type you probably haven't saved a lot of memory

Is not this because of the same long-standing issue?

```
// Base.qml

property Component component : Component {
   id: baseComponent
   SomeType { }
}
```

```
// Child.qml
Base {
   component: Component {
     id: childComponent
     SomeOtherType { }
   }
}
```

QML does not currently allow a way to disable creating `baseComponent`.

I read that this is not fixed because of side-effects. But `Component` 
is not something that can cause side-effects (can it?).

So perhaps `Component` can be treated differently: 1) always garbage 
collected (does not have parent), so when not referred, it is destroyed. 
2) all `Component` properties are deferred by default (so it is not even 
created in the first place). What do you think?

 > What we should actually do is expose deferred properties to QML

That would be really helpful, but as far as I see it does not help with 
these:

- The component is changed in derived type at any arbitrary time.
- The property has a complex binding that we want to avoid repeating in 
the derived type.

My understanding is that the garbage collection approach would be fine 
with both.

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