Elapsed time since last logged date function. Returns a string representation of time elapsed since a date.

elaspedTime.swift

  /// Returns a string representation of the time elapsed since the entry was logged.
  /// It works at 4 resolutions:
  /// - Full:  "5yr, 6mo, 3d, 4h, 25m, 35s"
  /// - Years/Months: "5yr, 6mo"
  /// - Days/Hours: "3d, 4h"
  /// - Minutes/Seconds: "25m, 35s"
  /// - Note: Only non-zero values are rendered: "24m" instead of "24m, 0s"
  /// - Parameters:
  ///   - loggedDate: The Date when the record was first logged
  ///   - full: A flag that specifies the resolution: if true full resolution, if false scoped resolution
  /// - Returns: A string that represents elapsed time: "5yr, 6mo" or "5yr, 6mo, 3d, 4h, 25m, 35s"
  static func elaspedTimeSince(loggedDate: Date, full: Bool = true) -> String {
    
    enum ElapsedTimeScope {
      case full, year, day, minute
    }
    
    let elapsedTime = -loggedDate.timeIntervalSinceNow
    let secondsInMinute: TimeInterval = 60
    let secondsInHour: TimeInterval = 3600
    let secondsInDay: TimeInterval = 86400
    let secondsInYear: TimeInterval = 31536000
    let secondsInMonth: TimeInterval = 2592000 // Average month length in seconds (30 days)
    
    let years = Int(elapsedTime / secondsInYear)
    let months = Int((elapsedTime.truncatingRemainder(dividingBy: secondsInYear)) / secondsInMonth)
    let days = Int((elapsedTime.truncatingRemainder(dividingBy: secondsInMonth)) / secondsInDay)
    let hours = Int((elapsedTime.truncatingRemainder(dividingBy: secondsInDay)) / secondsInHour)
    let minutes = Int((elapsedTime.truncatingRemainder(dividingBy: secondsInHour)) / secondsInMinute)
    let seconds = Int(elapsedTime.truncatingRemainder(dividingBy: secondsInMinute))
    
    var timeScope: ElapsedTimeScope = .minute // need to set a default value in case all time values are 0
    
    if full {
      timeScope = .full
    } else {
      if years != 0 || months != 0 {
        timeScope = .year
      } else {
        if days != 0 || hours != 0 {
          timeScope = .day
        } else {
          if minutes != 0 || seconds != 0 {
            timeScope = .minute
          }
        }
      }
    }
    
    var components: [String] = []
    
    switch timeScope {
    case .full:
      if years > 0 {
        components.append("\(years)yr")
      }
      if months > 0 {
        components.append("\(months)mo")
      }
      if days > 0 {
        components.append("\(days)d")
      }
      if hours > 0 {
        components.append("\(hours)h")
      }
      if minutes > 0 {
        components.append("\(minutes)m")
      }
      if seconds > 0 {
        components.append("\(seconds)s")
      }
    case .year:
      if years > 0 {
        components.append("\(years)yr")
      }
      if months > 0 {
        components.append("\(months)mo")
      }
    case .day:
      if days > 0 {
        components.append("\(days)d")
      }
      if hours > 0 {
        components.append("\(hours)h")
      }
    case .minute:
      if minutes > 0 {
        components.append("\(minutes)m")
      }
      if seconds > 0 {
        components.append("\(seconds)s")
      }
    }
        
    return components.joined(separator: full ? "," : ", ")
  }
  
}