How to Have Custom Relative Date-Time Formatting

[jama5262]

Overview

A recent issue was raised asking:

Issue #179

Does Jiffy support short messages?
Instead of "5 minutes ago", can it display "5m"?

As of version 6.4.0, Jiffy allows you to fully customize relative date-time formatting. Whether you want short-form messages or a completely new format, Jiffy provides flexible options.

How to Customize Relative Date-Time Formatting

There are two main ways to achieve this:

1️⃣ Extending e.g. EnRelativeDateTime (or Other Pre-Set Classes)

If you only need to override specific pre-set RelativeDateTime formats while keeping the rest, you can extend them. For this example, we will use EnRelativeDateTime

// Extend EnRelativeDateTime to modify specific formats
class CustomRelativeDateTime extends EnRelativeDateTime {
  @override
  String minutes(int minutes) => '$minutes' 'm'; // Custom short format
}

await Jiffy.setLocale('en_US', relativeDateTime: CustomRelativeDateTime());

final j = Jiffy.now().subtract(minutes: 5);
print(j.fromNow(withPrefixAndSuffix: false)); // Output: 5m

2️⃣ Creating a Fully Custom Relative Date-Time Class

If you need total control, you can create a custom class from scratch by implementing RelativeDateTime.

// Create a completely custom relative date-time class
class MyRelativeDateTime extends RelativeDateTime {
  @override
  String prefixAgo() => '';
  @override
  String suffixAgo() => '';
  @override
  String minutes(int minutes) => '$minutes' 'm';
  @override
  String hours(int hours) => '$hours' 'h';
  @override
  String days(int days) => '$days' 'd';
 ...
}

await Jiffy.setLocale('en_US', relativeDateTime: MyRelativeDateTime());

final j = Jiffy.now().subtract(days: 3);
print(j.fromNow(withPrefixAndSuffix: false)); // Output: 3d

More Customization Options

Beyond relative date-time formats, Jiffy allows advanced locale settings such as:

• ✅ Custom start-of-week configuration
• ✅ Custom ordinal suffixes (1st, 2nd, 3rd, etc.)
• ✅ Modifying how fromNow() and other time expressions appear

For full details, check out the Locale Support Documentation.

Hope this helps! Let me know if you have any questions. 🚀