scheduled.swift

import Foundation
import Combine

extension Timer {
    static func publish(at date: Date, tolerance: TimeInterval? = nil, on runLoop: RunLoop, in mode: RunLoop.Mode, options: RunLoop.SchedulerOptions? = nil) -> AnyPublisher<Date, Never> {
        let subject = PassthroughSubject<Date, Never>()

        let timer = Timer(fire: date, interval: 0, repeats: false) { _ in
            subject.send(Date())
            subject.send(completion: .finished)
        }

        if let tolerance = tolerance {
            timer.tolerance = tolerance
        }

        runLoop.add(timer, forMode: mode)

        return subject.handleEvents(receiveCancel: { [weak timer] in
            timer?.invalidate()
        }).eraseToAnyPublisher()
    }
}