PreciseISO8601DateFormatter

PreciseISO8601DateFormatter is a precise and specific date formatter. Apple’s built-in DateFormatter and ISO8601DateFormatter are only capable of parsing milliseconds. Many services return dates with nanosecond precision in the format yyyy-MM-dd'T'HH:mm:ss.SSSSSS'Z'. PreciseISO8601DateFormatter is able to parse those strings and encode dates into that format.

PreciseISO8601DateFormatter is intended to be a drop-in replacement for DateFormatter or ISO8601DateFormatter. It’s a subclass of Formatter. Like Apple’s built-in date formatters, PreciseISO8601DateFormatter is thread-safe.

It’s important to note, if you supply the formatter with a date with nanosecond precision, encode it into a string, and then decode that string back into a date, the original date and the decoded date will be different. The decoded date will have lost its nanosecond precision (i.e., the date’s nanosecond component would go from 448814988 to 448814000). This means, if you use PreciseISO8601DateFormatter to decode the date-time strings returned by your server, you should also use this formatter to store the encoded date-time strings locally.

Usage

let formatter = PreciseISO8601DateFormatter()

let date = formatter.date(from: "2021-02-03T12:48:00.000123Z")
let string = formatter.string(from: date) // "2021-02-03T12:48:00.000123Z"

Installation

To use PreciseISO8601DateFormatter with the Swift Package Manager, add a dependency to your Package.swift file:

let package = Package(
  dependencies: [
    .package(url: "https://github.com/shareup/precise-iso-8601-date-formatter.git", from: "1.0.2")
  ]
)

License

The license for PreciseISO8601DateFormatter is the standard MIT licence. You can find it in the LICENSE file.