Swift date format with millisecond component

Question

All,

I have a date format "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'" and I need to set the millisecond value, but date component does not provide millisecond attribute.

Below is my code for setting custom values in hour, minute, second. I also need to set millisecond to 0/999 value.

static func getToadyStartInUTC() -> String{
    let todaydate = Date()
    let formatter = DateFormatter()
    
    var components = Calendar.current.dateComponents([.year, .month, .day, .hour], from: todaydate)
    components.hour = 0
    components.minute = 0
    components.second = 0

    let calendar = Calendar.current
    let startDate = calendar.date(from: components)!
    
    print("\(startDate)")
    
    formatter.timeZone = TimeZone(identifier: "UTC")
    formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
   return formatter.string(from: startDate)
}

How can I set the millisecond value in date component?

Are you passing the timestamp in milliseconds? If yes, what's your input and output? — Bharat, Jan 18 '21 at 15:48
@Bharat Right now my func return "2021-01-18T05:00:00.000Z" this date . I need to set millisecond to 999 . — Ravi, Jan 18 '21 at 15:57
Did you try components.nanosecond = milliseconds * 1000000 ? — Ptit Xav, Jan 18 '21 at 15:57

score 0 · Answer 1 · answered Jan 18 '21 at 16:09

An alternative solution with Calendar API to get startDate and ISO8601DateFormatter

static func getToadyStartInUTC() -> String {
    let todaydate = Date()
    var calendar = Calendar.current
    let timeZone = TimeZone(secondsFromGMT: 0)!
    calendar.timeZone = timeZone

    let startDate = calendar.startOfDay(for: todaydate)
    var components = calendar.dateComponents(in: timeZone, from: startDate)
    components.nanosecond = 999000000

    let formatter = ISO8601DateFormatter()
    formatter.formatOptions.insert(.withFractionalSeconds)
    return formatter.string(from: components.date!)
}

score 0 · Answer 2 · answered Oct 20 '21 at 05:59

let todaydate = Date()
    var calendar = Calendar.current
     
    calendar.timeZone = TimeZone(identifier: "UTC")


    let startDate = calendar.startOfDay(for: todaydate)
    var components = calendar.dateComponents(in: timeZone, from: startDate)
    components.nanosecond = 999000000

    let formatter = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"

   
     formatter.string(from: components.date!)

Swift date format with millisecond component

2 Answers2