Day 50 - @State vs @Observed again

Way back when, I was unclear about @StateObject and @ObservedObject (here , and here ). I still am.

But in today’s tutorial video, Paul clearly says that the @StateObject is for the single place in your app where the object is created, then everywhere else, use @ObservedObject. Trouble is, I just know from the Simple MVVM app I made if you wrap the single instance of the data model with the @ObservedObject, it still works.

Half way through my #100Days and this mystery is still not solved for me. I imagine now it never will be until I can figure out how the property wrappers differ. When you hold down command, and click over a keyword, you get a list of options. One of these options is “Jump to definition”.

So I should be able to do that with @StateObject and @ObservedObject then just diff the code and see right?

Obviously, I’m not comprehending all of this, but it looks like the main difference is this extra Wrapper struct in the ObservedObject:

@dynamicMemberLookup @frozen public struct Wrapper {
        public subscript<Subject>(dynamicMember keyPath: ReferenceWritableKeyPath<ObjectType, Subject>) -> Binding<Subject> { get }
    }

Yeah. I’m not going to be able to unpack that bad boy. I’ll just file it in “probably something to do with reference counting, and come back to it when I’m smarter.