10 Things I Wish I Knew When Starting SwiftUI (See also https://gist.github.com/steipete/6c430d08bd57b066fada7628d3b8b719)

SwiftUIThingsToKnow.swift

- In almost all cases where you type `@ObservedObject`, you really want `@StateObject`. 
If you need to support iOS 13, use `@State` on parent and pass value into child with `@ObservedObject` to simulate `@StateObject`.
Pass arguments to that model in `onAppear`. Example: https://github.com/ra1028/SwiftUI-Hooks/blob/main/Sources/Hooks/HookScope.swift#L39-L41

```
        .onAppear {
            model.onAppear(userTag: userTag)
        }
        .onDisappear {
            model.onDisappear()
        }
```

- Don't do work in your `View` struct inits. 
- Except if your view is dead-simple, you want one model per view (`class XYZModel: ObservableObject`).
- `didSet` doesn't work on `@State` but it works on `@Published`.
- Give your views a unique `id()` if they don't seem to reload.
- [assign(on:)](https://developer.apple.com/documentation/combine/fail/assign(to:)) is amazing and even manages lifetime. Use when your publishers don't need to change in a model.
- Put one `NavigationLink` in your view background to have fully flexible programmatic navigation. You can even build your own navigation stack quite easily.