Temporal.Duration.toLocaleString() does not return a proper human-readable string

[dahlia]

Version: Deno 2.0.5

Expected:

> Temporal.Duration.from('P1DT6H30M').toLocaleString()
"1 day 6 hours 30 minutes"

Actual:

> Temporal.Duration.from('P1DT6H30M').toLocaleString()
"P1DT6H30M"

See also:

https://tc39.es/proposal-temporal/docs/duration.html#toLocaleString

[MohammadSu1]

@bartlomieju I think the toLocaleString() function is not supported in Deno because, as mentioned in the attached document, it requires Intl.DurationFormat to work properly. I attempted to address the issue using the attached code as a workaround, but I couldn't identify the exact source of the problem.

Temporal.Duration.prototype.toLocaleString = function () {
  const parts = [];
  if (this.days) parts.push(`${this.days} day${this.days > 1 ? 's' : ''}`);
  if (this.hours) parts.push(`${this.hours} hour${this.hours > 1 ? 's' : ''}`);
  if (this.minutes) parts.push(`${this.minutes} minute${this.minutes > 1 ? 's' : ''}`);
  if (this.seconds) parts.push(`${this.seconds} second${this.seconds > 1 ? 's' : ''}`);
  return parts.length ? parts.join(' ') : '0 seconds';
};

Could you provide a hint on where Temporal is used so that I know where to begin making modifications?

[0f-0b]

This function will be implemented in V8 in the future. For now Intl.DurationFormat can be used instead. The polyfill below also works today.

const { bind, call } = Function.prototype;
const uncurryThis = bind.bind(call);

const Duration = Temporal.Duration;
const proto = Object.getOwnPropertyDescriptors(Duration.prototype);
const assertDuration = uncurryThis(proto.toLocaleString.value);
const getYears = uncurryThis(proto.years.get);
const getMonths = uncurryThis(proto.months.get);
const getWeeks = uncurryThis(proto.weeks.get);
const getDays = uncurryThis(proto.days.get);
const getHours = uncurryThis(proto.hours.get);
const getMinutes = uncurryThis(proto.minutes.get);
const getSeconds = uncurryThis(proto.seconds.get);
const getMilliseconds = uncurryThis(proto.milliseconds.get);
const getMicroseconds = uncurryThis(proto.microseconds.get);
const getNanoseconds = uncurryThis(proto.nanoseconds.get);

const DurationFormat = Intl.DurationFormat;
const proto2 = Object.getOwnPropertyDescriptors(DurationFormat.prototype);
const formatDuration = uncurryThis(proto2.format.value);

Object.assign(Duration.prototype, {
  toLocaleString(locales = undefined, options) {
    assertDuration(this);
    const durationFormat = new DurationFormat(locales, options);
    const duration = {
      years: getYears(this),
      months: getMonths(this),
      weeks: getWeeks(this),
      days: getDays(this),
      hours: getHours(this),
      minutes: getMinutes(this),
      seconds: getSeconds(this),
      milliseconds: getMilliseconds(this),
      microseconds: getMicroseconds(this),
      nanoseconds: getNanoseconds(this),
    };
    return formatDuration(durationFormat, duration);
  },
});

[bartlomieju]

@0f-0b could you open a PR with your polyfill?

[0f-0b]

I opened #27000.