Feat: skip default value emission

[IlCallo]

Sometimes it can be useful to skip the emission of the default value.
Not really sure about how it can be the API for this, maybe another decorator parameter or transforming the current decorator parameter to an option-bag?

[PSanetra]

Do you have a use case where you need to skip the emission of the default value? Is it not possible to solve these cases with the skip operator?

[IlCallo]

It is possible to achieve the same behaviour by creating an additional observable in the constructor based on the observable you generate, but at that point I have littered the code with an assignment in the constructor and a property (the one generated by this decorator) I'll actually never use.

Or I can re-assign it to your observable property, but that's pretty confusing code.

If, instead, there's a parameter which allow to skip the default emission, it's really clear and expressive what's happening just by looking at the property declaration :)

Tomorrow I'll try to remember which was the use case, it's been a while 😅

[IlCallo]

One use case is related to #3.
Right now no emission is fired for optional properties, but if it become possible without manually specifying 'undefined' it's highly possible that for some cases it will be useful to get the 'undefined' emission and for some others it would be better to keep old behaviour in which that initial value isn't emitted.

I cannot remember other use cases right now, I'll report back if I remember other ones