How to bind an EnvironmentObject variable to a slider - swiftui

Question

I have a sliderVal that needs to be accessed in various other places, so my understanding is that I should use a EnvironmentObject (or BindableObject, but EnvironmentObject was nice because this is used in the subviews as well) to hold those values. Something like this
struct ExampleView : View {
#EnvironmentObject var externalData : ExternalData
var body: some View {
Slider(value: self.externalData.$sliderVal, from: 1, through: 100, by: 1)
}
}
final class ExternalData : BindableObject {
let didChange = PassthroughSubject<ExternalData, Never>()
var sliderVal : Double = 5.0 {
didSet {
didChange.send(self)
}
}
}
This usually works for things like Text, however here, when I try to use the $ symbol to bind to something like a Slider, it gives a compile error of
Value of type 'ExternalData' has no member '$sliderVal'; did you mean 'sliderVal'?
But using just sliderVal gives me the error
Cannot convert value of type 'Double' to expected argument type 'Binding<_>'
Trying to use #State for sliderVal in my enviroment object builds successfully, but gives me this error at runtime
Fatal error: Accessing State<Double> outside View.body
Which makes since since #State things should be private.
What is the correct way to do this? I need to be able to access the sliderVal outside my view on a separate thread, so using a #Binding or #State doesn't work

Answer 1

I found an answer here, the trick is to move the $ and not use self:
struct ExampleView : View {
#EnvironmentObject var externalData : ExternalData
var body: some View {
Slider(value: $externalData.sliderVal, from: 1, through: 100, by: 1)
}
}
final class ExternalData : BindableObject {
let didChange = PassthroughSubject<ExternalData, Never>()
var sliderVal : Double = 5.0 {
didSet {
didChange.send(self)
}
}
}