Retrieve the size of an element within SwiftUI

GetSize.swift

struct ContentView_Previews: PreviewProvider {
	static var previews: some View {
		ContentView()
	}
}

struct ContentView: View {
	@State var hStackSize: CGSize = .zero

	var body: some View {
		HStack {
			Image(systemName: "tray.fill")
			Text("Beep boop")
		}
		.font(.title)
		.background(Color.pink)
		.getSize { size in
			hStackSize = size
		}
		.onChange(of: hStackSize) { newValue in
			print("New HStack Size is: \(hStackSize)")
		}
	}
}

struct SizeReader: PreferenceKey {
	static var defaultValue: CGSize = .zero
	static func reduce(value: inout CGSize, nextValue: () -> CGSize) {
		value = nextValue()
	}
}

extension View {
	func getSize(size: @escaping (CGSize) -> Void) -> some View {
		return self
			.background(
				GeometryReader { geometry in
					Color.clear
						.preference(key: SizeReader.self, value: geometry.size)
						.onPreferenceChange(SizeReader.self) { value in size(value) }
				}.hidden()
			)
	}
}