Humanize durations - New Intl.DurationFormat 2025 release

[jantoney]

I honestly haven't used the package before (this will be my first time) but I was looking through docs and found this line

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Luxon does not (yet) have an equivalent of Moment's Duration humanize method. Luxon will add that when Intl.UnitFormat is supported by browsers.

Luxon Docs - For Moment users

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I had a look around and that link hasn't had an update for 8 years.
Searching further, I found Intl.DurationFormat which seems to be a new 2025 thing and supported by all major browsers, and via my basic look, seems to meet the humanize objective...?

So was hoping to pop this onto the feature request list again please.

[diesieben07]

The documentation is a bit outdated in this regard.

A closer equivalent to Moment's humanize would be Intl.RelativeTimeFormat, which Luxon exposes through DateTime.toRelative:

const now = DateTime.now();
const tomorrow = now.plus({days: 1});
console.log(tomorrow.toRelative({ base: now })); // in 1 day

With Intl.DurationFormat you'd just get 1 day.
Additionally, Intl.RelativeTimeFormat always formats only one unit and Intl.DurationFormat always formats all the units.

Luxon exposes something similar to Intl.DurationFormat using Duration.toHuman, it is based on Intl.NumberFormat and Intl.ListFormat. This could be updated to use Intl.DurationFormat in supported browsers.

Another possible addition would be something like Duration.toRelative(unit) which would convert the Duration to that unit and then use RelativeTimeFormat, like DateTime.toRelative.

I'll look into updating the documentation.