SwiftUI: DisclosureGroup "expansion handler" to only have one group expanded at a time, and automatically hiding the last one, when expanding a new one.

ExpansionHandler.swift

class ExpansionHandler<T: Equatable>: ObservableObject {
    @Published private (set) var expandedItem: T?

    func isExpanded(_ item: T) -> Binding<Bool> {
        return Binding(
            get: { item == self.expandedItem },
            set: { self.expandedItem = $0 == true ? item : nil }
        )
    }

    func toggleExpanded(for item: T) {
        self.expandedItem = self.expandedItem == item ? nil : item
    }
}

// Usage:
// Some `Equatable` type, can also use basic types like `String` or `Date`.
enum ExpandableSection: Equatable {
    case section
    case anotherSection
}

@StateObject private var expansionHandler = ExpansionHandler<ExpandableSection>()

DisclosureGroup(
    isExpanded: self.expansionHandler.isExpanded(.section),
    content: {
        // ...
    },
    label: {
        // ...
    }
)
.contentShape(Rectangle()) // Usability feature to have the whole item tappable, and not just the label/disclosure indicator
.onTapGesture {
    withAnimation { self.expansionHandler.toggleExpanded(for: .section) }
}

Works as a charm! Kudos!!! 🚀🚀🚀