@swift-5.0.3
import Foundation let gregorian = Calendar(identifier: .gregorian) let utc = TimeZone(identifier: "UTC")! let components = gregorian.dateComponents(in: utc, from: Date()) func date(from components: DateComponents, with nanosecond: Int) -> Date { var components = components components.nanosecond = nanosecond return components.date! } print(date(from: components, with: 999499976).description) print(date(from: components, with: 999499977).description)