Function getFormatOptions

packages/react-stately/src/datepicker/utils.ts:184–229

(
  fieldOptions: FieldOptions,
  options: FormatterOptions
)

};

export function getFormatOptions(
  fieldOptions: FieldOptions,
  options: FormatterOptions
): Intl.DateTimeFormatOptions {
  let defaultFieldOptions = options.shouldForceLeadingZeros
    ? TWO_DIGIT_FIELD_OPTIONS
    : DEFAULT_FIELD_OPTIONS;
  fieldOptions = {...defaultFieldOptions, ...fieldOptions};
  let granularity = options.granularity || 'minute';
  let keys = Object.keys(fieldOptions);
  let startIdx = keys.indexOf(options.maxGranularity ?? 'year');
  if (startIdx < 0) {
    startIdx = 0;
  }

  let endIdx = keys.indexOf(granularity);
  if (endIdx < 0) {
    endIdx = 2;
  }

  if (startIdx > endIdx) {
    throw new Error('maxGranularity must be greater than granularity');
  }

  let opts: Intl.DateTimeFormatOptions = keys.slice(startIdx, endIdx + 1).reduce((opts, key) => {
    opts[key] = fieldOptions[key];
    return opts;
  }, {});

  if (options.hourCycle != null) {
    opts.hour12 = options.hourCycle === 12;
  }

  opts.timeZone = options.timeZone || 'UTC';

  let hasTime = granularity === 'hour' || granularity === 'minute' || granularity === 'second';
  if (hasTime && options.timeZone && !options.hideTimeZone) {
    opts.timeZoneName = 'short';
  }

  if (options.showEra && startIdx === 0) {
    opts.era = 'short';
  }

  return opts;
}

export function getPlaceholderTime(placeholderValue: DateValue | null | undefined): TimeValue {
  if (placeholderValue && 'hour' in placeholderValue) {