Format yyyy-MM-dd'T'HH:mm:ss.SSSZ swift not work

Question

i get from json the following format, specifically these are two of the ones I get:

  "createdAt":"2020-09-21T18:24:36.787Z",

  "createdAt":"2020-09-21T18:45:05.250Z",

I used this format:

    lazy var formatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
    formatter.timeZone = TimeZone(abbreviation: "UTC+8")
    formatter.locale = Locale.current
    formatter.dateStyle = .medium
    formatter.timeStyle = .none
    return formatter
}()

however, the application only gives me back:

Sep 22, 2020
Sep 22, 2020

why is it not time?

Leo Dabus · Answer 1 · 2020-11-17T22:56:55.793

Z in your date string means UTC The "Z" in your dateFormat "yyyy-MM-dd'T'HH:mm:ss.SSSZ" will interprete that as UTC. It doesn't matter which timezone you set your date formatter to. It will only make a difference when getting a string from a Date. Btw You should always set your dateFormatter locale to "en_US_POSIX" before setting the dateFormat when parsing fixed date formats.

Besides that you can not use dateFormat and date/time styles together. It is one or the other.

let formatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.locale = .init(identifier: "en_US_POSIX")
    formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
    formatter.timeZone = TimeZone(secondsFromGMT: 0)
    return formatter
}()

if let date = formatter.date(from: "2020-09-21T18:24:36.787Z") {
    print(date.description(with: .current))  // Monday, 21 September 2020 15:24:36 Brasilia Standard Time
    let dateString = formatter.string(from: date)
    print("date:", dateString)
}

This will print:

Monday, 21 September 2020 15:24:36 Brasilia Standard Time
date: 2020-09-21T18:24:36.787+0000

If you need to display a localized date to the user check this post

Rob · Answer 2 · 2020-11-18T01:37:19.413

Two options for building and parsing ISO 8601/RFC 3339 date/time strings:

Use DateFormatter with no “styles”, but specify X for the timezone:

let formatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.locale = Locale(identifier: "en_US_POSIX")
    formatter.timeZone = TimeZone(secondsFromGMT: 0)
    formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSX"
    return formatter
}()

Ironically, note the X rather than Z, to make sure that when you are building strings from dates, that the timezone is shown as Z rather +0000.

Use ISO8601DateFormatter:

let formatter: ISO8601DateFormatter = {
    let formatter = ISO8601DateFormatter()
    formatter.formatOptions.insert(.withFractionalSeconds)
    return formatter
}()

Format yyyy-MM-dd'T'HH:mm:ss.SSSZ swift not work

2 Answers2