`@std/fmt/duration`: `ignoreZeros` seems broken

[sakgoyal]

Describe the bug
the ignoreZero flag seems to ignore leading zeros:

Steps to Reproduce

format(785000, { style: "digital", ignoreZero: true })
> "00:00:13:05" // expected: "13:05"

Expected behavior
expected: "13:05"

Environment

• OS: Win10
• deno version: 2.1.4
• std version: 1.0.3

[GriffinJohnston]

This is the expected behavior. For style: "digital" only zeros at the end are ignored. See https://jsr.io/@std/fmt/doc/duration/~/FormatOptions#property_ignorezero

[sakgoyal]

I see. is there anything I can do to make it remove leading zeros too? perhaps a new option to do that?

[kt3k]

I'm not sure that option makes sense. If the leading zeros removed, there's no difference between "00:00:13:05" and "00:13:05:00" (both become "13:05", and I think that would be confusing)

[sakgoyal]

I see your point. But, wouldn't that be up to the developer to choose what is the right option for them to use? the library should allow the developer flexibility on what they want to do.

I think a good implementation would be changing the api so the settings change from
ignoreZeros: boolean to
ignoreZeros: "left" | "right" | "both"

[kt3k]

I'm skeptical that adding option is worth it as string method of javascript is enough flexible to support this kind of situation. If you prefer to strip the leading zeros you can do:

format(785000, { style: "digital", ignoreZero: true }).replace(/^(00:)+/g, "")

[timreichen]

I think the current duration api is not very flexible. Intl.DurationFormat.prototype.format() is more flexible and supports locale, but sadly is not implemented in deno. The proper way of handling this would probably be to adapt the current implementation to mirror Intl.DurationFormat.prototype.format() and also request that deno implements it natively.