Date.VerbatimFormatStyle

This is part of the FormatStyle Deep Dive series

The Date.VerbatimFormatStyle outputs a date string that bypasses the locale on your device. You use a special format string to composite a date out of parts, and can specify the calendar and time zone for the display.


Download the Xcode Playground with all examples

See the examples as a gist


Sidenote: The VerbatimFormatStyle is a strange one. As of this writing, the apple docs are empty and the headers contain the following line: “Formats a Date using the given format.”

What cracked the code is a post on the Swift Evolution Forums about outputting 24 hour time using the new FormatStyle

There’s no extension on FormatStyle that lets you quickly access a VerbatimFormatStyle instance. You’re stuck creating a new instance and Extending FormatStyle yourself.

let twosdayDateComponents = DateComponents(
    year: 2022,
    month: 2,
    day: 22,
    hour: 2,
    minute: 22,
    second: 22,
    nanosecond: 22
)
let twosday = Calendar(identifier: .gregorian).date(from: twosdayDateComponents)!

let verbatim = Date.VerbatimFormatStyle(
    format: "\(hour: .twoDigits(clock: .twentyFourHour, hourCycle: .oneBased)):\(minute: .twoDigits)",
    timeZone: TimeZone.current,
    calendar: .current
)
verbatim.format(twosday) // "02:22"

The format property on the init method is of type Date.FormatString, this uses the string interpolation system under the hood. You have access to all of the date Date.FormatStyle.Symbol values used in the Date.FormatStyle.datTime style.

Hours are different, there’s a special Date.FormatStyle.Symbol.VerbatimHour type to represent the hour. It gives you the ability to display a 24 hour clock, instead of a 12 hour clock as well as zero pad the hours.


Attributed String Output

AttributedString output can be had by this formatter by adding the .attributed parameter to the FormatStyle during use.

You can read more details in the AttributedString Output deep-dive


Download the Xcode Playground with all examples

See the examples as a gist


Tags: