Bug 285078 – Intl.DurationFormat in digital style breaks the output when hoursDisplay is "auto"

• Component: JavaScriptCore
• Status: RESOLVED FIXED

Note: the issue can be reproduced on iOS 18 only.

const instance = new Intl.DurationFormat('en-US', {
  style: "digital",
  hoursDisplay: "auto",
})


Expected behavior:
instance.format({hours: 0, minutes: 1, seconds: 2});     // "01:02"


Current behavior:
instance.format({hours: 0, minutes: 1, seconds: 2});     // ":, 01:02"


Separators shouldn't be part of the output.

[Alexey Proskuryakov]

Thank you for the report! Could you please clarify what you mean by "can be reproduced on iOS 18 only"? One can interpret this in multiple ways (e.g. that it doesn't reproduce in Safari on macOS, or doesn't reproduce on iOS 17.x, or doesn't reproduce in iOS 18.2).

[Karl Dubost]

Confirmed on macOS 15.2
tested on 

```
":, 01:02" Safari Technology Preview 209 20621.1.6
"01:02" Firefox Nightly 135.0a1 13524.12.18
"01:02" Google Chrome Canary 133.0.6914.0  6914.0
```

[Radar WebKit Bug Importer]

<rdar://problem/141969050>

[Karl Dubost]

To note that 
instance.format({hours: 1, minutes: 2, seconds: 3});

returns the same results in all browsers
"1:02:03"

[Karl Dubost]

In Safari:
Also `instance.formatToParts({hours: 0, minutes: 1, seconds: 2})`

```
[ 
  {type: "literal", value: ":"}, 
  {type: "literal", value: ", "}, 
  {type: "integer", value: "01", unit: "minute"}, 
  {type: "literal", value: ":"}, 
  {type: "integer", value: "02", unit: "second"}
]
```

while  `instance.formatToParts({hours: 1, minutes: 2, seconds: 3})`

```
[
  {type: "integer", value: "1", unit: "hour"}, 
  {type: "literal", value: ":"}, 
  {type: "integer", value: "02", unit: "minute"}, 
  {type: "literal", value: ":"}, 
  {type: "integer", value: "03", unit: "second"}
]
```

In Firefox/Chrome

```
[
  {"type": "integer", "value": "01","unit": "minute"},
  {"type": "literal", "value": ":"},
  {"type": "integer", "value": "02", "unit": "second"}
]
```

So there is also an issue with `formatToParts`

[Karl Dubost]

It's a bit of a mess. 

instance.format({years: 1, days: 3, hours: 1, minutes: 2, seconds: 3});
     "1 yr, 3 days, 1:02:03"  (everywhere)

instance.format({years: 1, days: 3, hours: 0, minutes: 2, seconds: 3});
     "1 yr, 3 days:02:03"  Safari, Firefox 
     "1 yr, 3 days, 02:03" Chrome

instance.format({years: 0, days: 3, hours: 1, minutes: 2, seconds: 3}); 
     "3 days, 1:02:03"  (everywhere)

instance.format({years: 0, days: 0, hours: 0, minutes: 2, seconds: 3}); 
     "02:03"  Firefox, Chrome
     ":, 02:03" Safari


instance.format({hours: -0, minutes: -2, seconds: -3}); 
instance.format({hours: 0, minutes: -2, seconds: -3}); 
    "-02:03" Firefox, Chrome
    ":, 02:03"  Safari

[Karl Dubost]

const instanceFR = new Intl.DurationFormat('fr-FR', {
  style: "digital",
  hoursDisplay: "auto",
})

instanceFR.format({hours:0, minutes: 2, seconds: 3})
    "02:03" Firefox, Chrome
    ": et 02:03" Safari

[Sosuke Suzuki]

Pull request: https://github.com/WebKit/WebKit/pull/38357

[EWS]

Committed 288277@main (5e50f4025022): <https://commits.webkit.org/288277@main>

Reviewed commits have been landed. Closing PR #38357 and removing active labels.