Example code for article about UndoManager - Managing a History

History.swift

class HistoryService {

    // 1
    let undoManager = UndoManager()
    var history = [Command]()

    // 2
    var canUndo: Bool { undoManager.canUndo }
    func undo() {
        guard canUndo else { return }
        undoManager.undo()
    }

    // 3
    var canRedo: Bool { undoManager.canRedo }
    func redo() {
        guard canRedo else { return }
        undoManager.redo()
    }
    
    // ...
}