ProgressManager

ProgressManager is a class to make dealing with Progress and its child tasks just a bit more straightforward and easy. Why use it? It allows for granular but accessible control over the details of a multistep operation, while automatically mirroring its state in views like ProgressView, UIProgressView, and NSProgressIndicator.

How to Use ProgressManager

Create a type that you'd like to use for referencing each child task (most easily an enumeration, but could be anything that conforms to ChildProgressTask). It must have two properties: childUnits and parentUnits. See docs for more info on each.

private enum ProgressSteps: ChildProgressTask {
    case importantStep, smallStep, aMultiUnitStep
    
    var childUnits: Int64 {
        switch self {
        // 1 unit of this task must be completed for it to be considered "complete" by the parent
        case .importantStep: 1
        // 1 unit of this task must be completed for it to be considered "complete" by the parent
        case .smallStep: 1
        // 6 units of this task must be completed for it to be considered "complete" by the parent
        case .aMultiUnitStep: 6
        }
    }
    
    var parentUnits: Int64 {
        switch self {
        // Once all units of this child task have been completed (1 unit),
        // it counts as 5 units in the context of the parent progress
        case .importantStep: 5
        // Once all units of this child task have been completed (1 unit),
        // it counts as 1 unit in the context of the parent progress
        case .smallStep: 1
        // Once all units of this child task have been completed (6 units),
        // it counts as 1 unit in the context of the parent progress
        case .aMultiUnitStep: 1
        }
    }
}

Then create an instance of ProgressManager using your type. When initializing your ProgressManager, you only need to provide it with a Set of the tasks that it cares about. If your type conforms to CaseIterable, you can even exclude the childTasks parameter of the initializer.

let progress = ProgressManager(
    // can be ommitted if type can be inferred
    ProgressSteps.self,
    // a Set of unique child tasks
    childTasks: [.importantStemp, .smallStep, .aMultiUnitStep]
)

As your code completes the tasks, you call any combination of the child task updating functions (setCompletedUnitCount(_:forChildTask:), addToCompletedUnitCount(_:forChildTask:), and updateCompletedUnitCount(forChildTask:updateClosure:)).

// Perform `.importantStep`.
progress.setCompletedUnitCount(1, forChildTask: .importantStep)

// Perform `.smallStemp`.
progress.setCompletedUnitCount(1, forChildTask: .smallStemp)

// Perform `.aMultiUnitStep`.
for i in 0..<6 {
    progress.addToCompletedUnitCount(i, forChildTask: .aMultiUnitStep)
}

And that's it! If you need more granular control, you can access the child tasks by either the childTasks property or just via the subscript (progress[.aMultiUnitStep]).