Add format()

[munierujp]

Usage:

import { parse , format } from 'duration-fns'

const duration = parse('PT1M30S')
console.log(format(duration, 'mm:ss'))  // 01:30

[dlevs]

Hi @munierujp,

As with #4, I think this is outside of the scope if this package. This can be achieved easily with a third party library, or plain JS.

I think libraries like "date-fns" have a compelling reason to supply a format function, since each component of a date can be expressed in many different ways. I don't see the same value in providing such a function for durations as they seem much simpler to me. If we did implement this for duration, we'd have to handle edge cases, like...

• What is the output of format({ minutes: 400 }, 'mm:ss')? 400:00?
• What is the output of format({ months: 1 }, 'mm:ss')?
• What would be the full list of units available? Just 'mm' and 'ss', or more?

I may be looking at this from the wrong perspective. If you have any other examples or can provide more context to demonstrate the value of this, let me know.

[dlevs]

Closing due to lack of activity