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HomeiOS DevelopmentFormatting dates in Swift utilizing Date.FormatStyle on iOS 15 – Donny Wals

Formatting dates in Swift utilizing Date.FormatStyle on iOS 15 – Donny Wals


Printed on: Might 27, 2022

Working with dates isn’t simple. And displaying them to your customers within the right locale hasn’t at all times been simple both. With iOS 15, Apple launched a brand new option to convert Date objects from and to String. This new method comes within the type of the brand new Formatter api that replaces DateFormatter.

As any seasoned iOS developer will let you know, DateFormatter objects are costly to create, and therefor type of tedious to handle appropriately. With the brand new Formatter api, we now not have to work with DateFormatter. As a substitute, we will ask a date to format itself based mostly on our necessities in a extra performant, simpler to make use of method.

On this put up I’ll present you how one can convert Date objects to String in addition to how one can extract a Date from a String.

Changing a Date to a String

Essentially the most easy option to convert a Date to a String is the next:

let formatted = Date().formatted() // 5/26/2022, 7:52 PM

By default, the formatted() perform makes use of a compact configuration for our String. The best way formatted() converts our Date to String takes into consideration the consumer’s present locale. For instance, if my system was set to be in Dutch, the date can be formatted as 26-5-2022 19:54 which is a extra acceptable formatting for the Dutch language.

Nonetheless, this won’t at all times be what we want. For instance, we would wish to have our date formatted as Might 26 2022, 7:52 PM. We are able to use the next code to do this:

let formatted = Date().formatted(
    .dateTime
        .day().month(.vast).yr()
        .hour().minute()
)

Let’s break this code aside a bit. The formatted perform takes an object that conforms to the FormatStyle protocol as its argument. There are numerous methods for us to create such an object. The FormatStyle protocol has a number of handy extensions that may present us with a number of completely different formatters.

For instance, when sending a Date to a server, we’ll usually have to ship our dates as ISO8601 compliant strings. Earlier than I clarify the code you simply noticed, I wish to present you how one can seize an ISO8601 compliant string from the present Date.

let formatted = Date().formatted(.iso8601) // 2022-05-26T18:06:55Z

Neat, huh?

Okay, again to the instance from earlier than. The .datetime formatter is used as a foundation for our customized formatting. We are able to name numerous capabilities on the article that’s returned by the .datetime static property to pick out the data that we wish to present.

A few of these properties, just like the month, may be configured to specify how they need to be formatted. Within the case of .month, we will select the .vast formatting to spell out the complete month title. We might use .slender to abbreviate the month all the way down to a single letter, or we might use one of many different choices to signify the month in numerous methods.

In case you omit a property, like for instance .yr(), our formatted date will omit the yr that’s embedded within the Date. And once more, the underlying formatter will at all times routinely respect your consumer’s locale which is de facto handy.

One other option to format the date is to by specifying the way you need the date and time to be formatted respectively:

let formatted = Date().formatted(date: .full, time: .commonplace) // Thursday, Might 26, 2022, 8:15:28 PM

The above offers a really verbose formatted string. We are able to make a extra compact one utilizing the next settings:

let formatted = Date().formatted(date: .abbreviated, time: .shortened) // Might 26, 2022, 8:16 PM

It’s even potential to omit the date or time completely by utilizing the .omitted possibility:

let formatted = Date().formatted(date: .abbreviated, time: .omitted) // Might 26, 2022

There are tons of various mixtures you could possibly give you so I extremely suggest you discover this api some extra to get a way of how versatile it truly is.

Making a Date from a String

Changing String to Date is barely much less handy than going from a Date to a String but it surely’s nonetheless not too unhealthy. Right here’s how you could possibly cowl the widespread case of changing an ISO8601 compliant string to a Date:

let string = "2022-05-26T18:06:55Z"
let expectedFormat = Date.ISO8601FormatStyle()
let date = strive! Date(string, technique: expectedFormat)

We make use of the Date initializer that takes a string and a formatting technique that’s used to parse the string.

We are able to additionally use and configure an occasion of FormatStyle to specify the elements that we count on to be current in our date string and let the system parse it utilizing the consumer’s locale:

let string = "Might 26, 2022, 8:30 PM"
let expectedFormat = Date.FormatStyle()
    .month().yr().day()
    .hour().minute()
let date = strive! Date(string, technique: expectedFormat)

The order of our date elements doesn’t matter; they’ll routinely be rearranged to match the consumer’s locale. That is tremendous highly effective, but it surely does imply that we will’t use this to parse dates on units that use a distinct locale than the one which matches the string’s locale. The very best locale agnostic date string is ISO8601 so you probably have management over the date strings that you just’ll parse, be sure to use ISO8601 when potential.

Abstract

On this brief article, you discovered how you need to use iOS 15’s FormatStyle to work format Date objects. You noticed how one can go from Date to String, and the opposite method round. Whereas FormatStyle is extra handy than DateFormatter, it’s iOS 15 solely. So when you’re nonetheless supporting iOS 14 you’ll wish to be sure to take a look at DateFormatter too.

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