Add an object type and utils for durations

[bjuppa]

Create factory function Duration for duration objects (time-period, span, stretch), like 3 days, 4 hours, 25 minutes.

Some resolution units to consider, each can be negative, at least one needs to be given:

Time-level:

• milliseconds
• seconds
• minutes
• hours

Days-level:

• days
• weeks

Months-level:

• months
• quarters
• years
• decades
• centuries
• millennia

Upon object creation, normalize / balance to the largest given unit within each level.

Properties and methods:

• iso
• toString() => iso
• toJson() => iso
• valueOf() => number tally milliseconds
• is(other: Duration) => boolean equality check
• round() => Duration
• rescale(shape: SloppyDuration) => Duration
• add(duration: Duration): Duration
• subtract(duration: Duration): Duration
• asHours(), asDays(), etc

Use Intl number format to localise strings using units. See how Luxon does this!
Check Temporal for balancing https://tc39.es/proposal-temporal/docs/balancing.html and compare that to Luxon's round, rescale & shift!

[bjuppa]

These are just my quick thoughts jotted down! ☝️

Please contribute your ideas about balancing/rescaling/normalizing!

[bjuppa]

For creating human readable strings of a duration, we should look into Intl RelativeTimeFormat

https://www.raymondcamden.com/2024/03/07/using-intlrelativetimeformat-for-localized-relative-timings