{"id":34815,"date":"2022-01-26T15:52:53","date_gmt":"2022-01-26T20:52:53","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=34815"},"modified":"2025-10-29T09:38:58","modified_gmt":"2025-10-29T13:38:58","slug":"swift-foundation-formatter-improvements","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2022\/01\/26\/swift-foundation-formatter-improvements\/","title":{"rendered":"Swift Foundation Formatter Improvements"},"content":{"rendered":"

Keith Harrison<\/a>:<\/p>\n

Unfortunately the documentation is not great so here’s a summary starting with date formatting.<\/p>

[…]<\/p>

In iOS 15 you apply the formatting directly to the Date without the need to create (and cache) a formatter. For example, the formatted(date:time)<\/code> method applies predefined date and time styles[…]<\/p>

[…]<\/p>

You customize the output by adding fields to the style. The output then contains just the fields you want:<\/p>

now.formatted(.dateTime.year().day().month()) \/\/ Jan 23, 2022<\/pre>\n
[…]<\/p>\n
If you add the .attributed<\/code> field to a format you get back a formatted attribute string. This is handy when you want to format components of the output[…]<\/p><\/blockquote>\n
The above example is for localized formatting, so the order that you specify the fields in doesn’t matter, and the styles and spellings are subject to the user’s settings.<\/p>\n
To specify exactly the format that you want, there’s a new type-safe alternative to format strings. Instead of:<\/p>\n
let dateFormatter = DateFormatter()\ndateFormatter.dateFormat = \"yyyy-MM-dd\"\ndateFormatter.string(from: date)<\/pre>\n
You can write:<\/p>\n
date.formatted(Date.VerbatimFormatStyle(format: \"\\(year: .defaultDigits)-\\(month: .twoDigits)-\\(day: .twoDigits)\", \n                                        timeZone: .current, \n                                        calendar: .current))<\/pre>\n
Yes, unfortunately this method leads to long code lines. And you probably still need to use Locale(identifier: \"en_US_POSIX\")<\/code> to get dependable results.<\/p>\n\n
Previously:<\/p>\n