[Interest] getting type information of properties in QML

[Ulf Hermann]

> 1) value types are always copied

Sort of. Most value types still look like JavaScript objects which are 
passed by reference. Internally, the reference nature is simulated by 
copying the data into a local and two-way-synchronizing with the 
original. This becomes expensive if either side changes often and/or the 
type has a lot of data.

> 3) types like int are not value types so they have to be treated 
> differently in your case. However, Number.isInteger(n) may get you close.

Numbers are still value types. What makes them special is that they are 
not objects in JavaScript and therefore not passed as reference. And you 
can also not use instanceOf on non-objects.

best regards,
Ulf