locale.html

<emu-clause id="locale-objects">
  <h1>Locale Objects</h1>

  <ins class="block">
  <emu-clause id="sec-locale-abstracts">
    <h1>Abstract Operations for Locale Objects</h1>

    <emu-clause id="sec-create-array-from-list-or-restricted" type="abstract operation">
      <h1>
        CreateArrayFromListOrRestricted (
          _list_: a List of ECMAScript language values,
          _restricted_: an ECMAScript language value*,
        ): an Array
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. If _restricted_ is not *undefined*, then
          1. Set _list_ to &laquo; _restricted_ &raquo;.
        1. Return CreateArrayFromList( _list_ ).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-calendars-of-locale" type="abstract operation">
      <h1>
        CalendarsOfLocale (
          _loc_: an Intl.Locale,
        ): an Array
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. Let _restricted_ be _loc_.[[Calendar]].
        1. Let _locale_ be _loc_.[[Locale]].
        1. Let _list_ be a List of one or more unique calendar types in canonical form (<emu-xref href="#sec-calendar-types"></emu-xref>), sorted in descending preference of those in common use for date and time formatting in _locale_.
        1. Return CreateArrayFromListOrRestricted( _list_, _restricted_ ).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-collations-of-locale" type="abstract operation">
      <h1>
        CollationsOfLocale (
          _loc_: an Intl.Locale,
        ): an Array
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. Let _restricted_ be _loc_.[[Collation]].
        1. Let _locale_ be _loc_.[[Locale]].
        1. Let _list_ be a List of one or more unique collation types in canonical form (<emu-xref href="#sec-collation-types"></emu-xref>), of those in common use for string comparison in _locale_. The values *"standard"* and *"search"* must be excluded from _list_. The list is sorted according to lexicographic code unit order.
        1. Return CreateArrayFromListOrRestricted( _list_, _restricted_ ).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-hour-cycles-of-locale" type="abstract operation">
      <h1>
        HourCyclesOfLocale (
          _loc_: an Intl.Locale,
        ): an Array
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. Let _restricted_ be _loc_.[[HourCycle]].
        1. Let _locale_ be _loc_.[[Locale]].
        1. Let _list_ be a List of one or more unique hour cycle identifiers, which must be lower case String values indicating either the 12-hour format (*"h11"*, *"h12"*) or the 24-hour format (*"h23"*, *"h24"*), sorted in descending preference of those in common use for date and time formatting in _locale_.
        1. Return CreateArrayFromListOrRestricted( _list_, _restricted_ ).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-numbering-systems-of-locale" type="abstract operation">
      <h1>
        NumberingSystemsOfLocale (
          _loc_: an Intl.Locale,
        ): an Array
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. Let _restricted_ be _loc_.[[NumberingSystem]].
        1. Let _locale_ be _loc_.[[Locale]].
        1. Let _list_ be a List of one or more unique numbering system identifiers in canonical form (<emu-xref href="#sec-numberingsystem-identifiers"></emu-xref>), sorted in descending preference of those in common use for formatting numeric values in _locale_.
        1. Return CreateArrayFromListOrRestricted( _list_, _restricted_ ).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-time-zones-of-locale" type="abstract operation">
      <h1>
        TimeZonesOfLocale (
          _loc_: an Intl.Locale,
        ): an Array
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. Let _region_ be GetLocaleRegion(_loc_.[[Locale]]).
        1. Assert: _region_ is not *undefined*.
        1. Let _list_ be a List of unique canonical time zone identifiers, which must be String values indicating a canonical Zone name of the IANA Time Zone Database, of those in common use in _region_. The list is empty if no time zones are commonly used in _region_. The list is sorted according to lexicographic code unit order.
        1. Return CreateArrayFromList( _list_ ).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-locale-is-right-to-left" type="abstract operation">
      <h1>
        LocaleIsRightToLeft (
          _loc_: an Intl.Locale,
        ): a Boolean
      </h1>
      <dl class="header">
        <dt>description</dt>
        <dd>The following algorithm refers to Locale data specified in <a href="https://www.unicode.org/reports/tr35/tr35-general.html#Layout_Elements">UTS 35's Layouts Elements</a>.</dd>
      </dl>
      <emu-alg>
        1. Let _locale_ be _loc_.[[Locale]].
        1. Let _script_ be GetLocaleScript(_locale_).
        1. If _script_ is *undefined*, then
          1. Let _maximal_ be the result of the <a href="https://unicode.org/reports/tr35/#Likely_Subtags">Add Likely Subtags</a> algorithm applied to _locale_. If an error is signaled, return *false*.
          1. Set _script_ to GetLocaleScript(_maximal_).
          1. If _script_ is *undefined*, return *false*.
        1. If the default general ordering of characters within a line in _script_ is right-to-left, return *true*.
        1. Return *false*.
      </emu-alg>
      <emu-note>
        When the direction of default general ordering of characters within a line in the _script_ cannot be determined, or is not right-to-left, *false* will be returned.
      </emu-note>
    </emu-clause>

    <emu-clause id="sec-weekday-to-string" type="abstract operation">
      <h1>
        WeekdayToString (
          _fw_: a String,
        ): a String
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. For each row of <emu-xref href="#table-locale-first-day-option-value"></emu-xref>, except the header row, in table order, do
          1. Let _w_ be the name given in the Weekday column of the current row.
          1. Let _s_ be the name given in the String column of the current row.
          1. If _fw_ is equal to _w_, return _s_.
        1. Return _fw_.
      </emu-alg>

      <emu-table id="table-locale-first-day-option-value">
        <emu-caption>First <emu-not-ref>Day</emu-not-ref> String and Value</emu-caption>
        <table class="real-table">
          <thead>
            <tr>
              <th>Weekday</th>
              <th>String</th>
              <th>Value</th>
            </tr>
          </thead>
          <tr>
            <td>*"0"*</td>
            <td>*"sun"*</td>
            <td>*7*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"1"*</td>
            <td>*"mon"*</td>
            <td>*1*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"2"*</td>
            <td>*"tue"*</td>
            <td>*2*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"3"*</td>
            <td>*"wed"*</td>
            <td>*3*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"4"*</td>
            <td>*"thu"*</td>
            <td>*4*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"5"*</td>
            <td>*"fri"*</td>
            <td>*5*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"6"*</td>
            <td>*"sat"*</td>
            <td>*6*<sub>𝔽</sub></td>
          </tr>
          <tr>
            <td>*"7"*</td>
            <td>*"sun"*</td>
            <td>*7*<sub>𝔽</sub></td>
          </tr>
        </table>
      </emu-table>
    </emu-clause>

    <emu-clause id="sec-string-to-weekday-value" type="abstract operation">
      <h1>
        StringToWeekdayValue (
          _fw_: a String,
        ): an integral Number or *undefined*
      </h1>
      <dl class="header">
      </dl>
      <emu-alg>
        1. For each row of <emu-xref href="#table-locale-first-day-option-value"></emu-xref>, except the header row, in table order, do
          1. Let _s_ be the name given in the String column of the current row.
          1. Let _v_ be the name given in the Value column of the current row.
          1. If _fw_ is equal to _s_, return _v_.
        1. Return *undefined*.
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-week-info-of-locale" type="abstract operation">
      <h1>
        WeekInfoOfLocale (
          _loc_: an Intl.Locale,
        ): a Record
      </h1>
      <dl class="header">
        <dt>description</dt>
        <dd>The following algorithm refers to Locale data specified in <a href="https://www.unicode.org/reports/tr35/tr35-dates.html#Date_Patterns_Week_Elements">UTS 35's Week Elements</a>.</dd>
      </dl>
      <emu-alg>
        1. Let _locale_ be _loc_.[[Locale]].
        1. Let _r_ be a Record whose fields are defined by <emu-xref href="#table-locale-weekinfo-record"></emu-xref>, with values based on _locale_.
        1. Let _fws_ be _loc_.[[FirstDayOfWeek]].
        1. Let _fw_ be StringToWeekdayValue(_fws_).
        1. If _fw_ is not *undefined*, then
          1. Set _r_.[[FirstDay]] to _fw_.
        1. Return _r_.
      </emu-alg>

      <emu-note>
        The record's return values are determined by _locale_, in accordance with the specifications outlined in <a href="https://www.unicode.org/reports/tr35/tr35-dates.html#Week_Data">UTS 35's Week Data</a> and <a href="https://www.unicode.org/reports/tr35/tr35-dates.html#first-day-overrides">First Day Overrides</a>.
      </emu-note>

      <emu-table id="table-locale-weekinfo-record">
        <emu-caption>WeekInfo Record Fields</emu-caption>
        <table class="real-table">
          <thead>
            <tr>
              <th>Field Name</th>
              <th>Value</th>
              <th>Meaning</th>
            </tr>
          </thead>
          <tr>
            <td>[[FirstDay]]</td>
            <td>Integral Number value between *1*<sub>𝔽</sub> and *7*<sub>𝔽</sub>: *1*<sub>𝔽</sub> specifies Monday; *2*<sub>𝔽</sub> specifies Tuesday; *3*<sub>𝔽</sub> specifies Wednesday; *4*<sub>𝔽</sub> specifies Thursday; *5*<sub>𝔽</sub> specifies Friday; *6*<sub>𝔽</sub> specifies Saturday; and *7*<sub>𝔽</sub> specifies Sunday.</td>
            <td>The weekday value indicating which day of the week is considered the 'first' day, for calendar purposes.</td>
          </tr>
          <tr>
            <td>[[Weekend]]</td>
            <td>A List of one or more integral Number values, in ascending order, between *1*<sub>𝔽</sub> and *7*<sub>𝔽</sub>: *1*<sub>𝔽</sub> specifies Monday; *2*<sub>𝔽</sub> specifies Tuesday; *3*<sub>𝔽</sub> specifies Wednesday; *4*<sub>𝔽</sub> specifies Thursday; *5*<sub>𝔽</sub> specifies Friday; *6*<sub>𝔽</sub> specifies Saturday; and *7*<sub>𝔽</sub> specifies Sunday.</td>
            <td>The list of weekday values indicating which days of the week are considered as part of the 'weekend', for calendar purposes. Notice that the number of days in the weekend are different in each locale and may not be contiguous.</td>
          </tr>
        </table>
      </emu-table>
    </emu-clause>
  </emu-clause>
  </ins>

  <emu-clause id="sec-intl-locale-constructor">
    <h1>The Intl.Locale Constructor</h1>

    <p>
      The Locale constructor is the <dfn>%Intl.Locale%</dfn> intrinsic object and a standard built-in property of the Intl object.
    </p>

    <emu-clause id="sec-Intl.Locale">
      <h1>Intl.Locale ( _tag_ [ , _options_ ] )</h1>

      <p>
        When the `Intl.Locale` function is called with an argument _tag_ and an optional argument _options_, the following steps are taken:
      </p>

      <emu-alg>
        1. If NewTarget is *undefined*, throw a *TypeError* exception.
        1. Let _relevantExtensionKeys_ be %Intl.Locale%.[[RelevantExtensionKeys]].
        1. Let _internalSlotsList_ be &laquo; [[InitializedLocale]], [[Locale]], [[Calendar]], [[Collation]], <ins>[[FirstDayOfWeek]], </ins>[[HourCycle]], [[NumberingSystem]] &raquo;.
        1. If _relevantExtensionKeys_ contains *"kf"*, then
          1. Append [[CaseFirst]] to _internalSlotsList_.
        1. If _relevantExtensionKeys_ contains *"kn"*, then
          1. Append [[Numeric]] to _internalSlotsList_.
        1. Let _locale_ be ? OrdinaryCreateFromConstructor(NewTarget, *"%Intl.Locale.prototype%"*, _internalSlotsList_).
        1. If _tag_ is not a String and _tag_ is not an Object, throw a *TypeError* exception.
        1. If _tag_ is an Object and _tag_ has an [[InitializedLocale]] internal slot, then
          1. Let _tag_ be _tag_.[[Locale]].
        1. Else,
          1. Let _tag_ be ? ToString(_tag_).
        1. Set _options_ to ? CoerceOptionsToObject(_options_).
        1. If IsStructurallyValidLanguageTag(_tag_) is *false*, throw a *RangeError* exception.
        1. Set _tag_ to CanonicalizeUnicodeLocaleId(_tag_).
        1. Set _tag_ to ? UpdateLanguageId(_tag_, _options_).
        1. Let _opt_ be a new Record.
        1. Let _calendar_ be ? GetOption(_options_, *"calendar"*, ~string~, ~empty~, *undefined*).
        1. If _calendar_ is not *undefined*, then
          1. If _calendar_ cannot be matched by the <code>type</code> Unicode locale nonterminal, throw a *RangeError* exception.
        1. Set _opt_.[[ca]] to _calendar_.
        1. Let _collation_ be ? GetOption(_options_, *"collation"*, ~string~, ~empty~, *undefined*).
        1. If _collation_ is not *undefined*, then
          1. If _collation_ cannot be matched by the <code>type</code> Unicode locale nonterminal, throw a *RangeError* exception.
        1. Set _opt_.[[co]] to _collation_.
        1. <ins>Let _fw_ be ? GetOption(_options_, *"firstDayOfWeek"*, ~string~, ~empty~, *undefined*).</ins>
        1. <ins>If _fw_ is not *undefined*, then</ins>
          1. <ins>Set _fw_ to WeekdayToString(_fw_).</ins>
          1. <ins>If _fw_ cannot be matched by the <code>type</code> Unicode locale nonterminal, throw a *RangeError* exception.</ins>
        1. <ins>Set _opt_.[[fw]] to _fw_.</ins>
        1. Let _hc_ be ? GetOption(_options_, *"hourCycle"*, ~string~, &laquo; *"h11"*, *"h12"*, *"h23"*, *"h24"* &raquo;, *undefined*).
        1. Set _opt_.[[hc]] to _hc_.
        1. Let _kf_ be ? GetOption(_options_, *"caseFirst"*, ~string~, &laquo; *"upper"*, *"lower"*, *"false"* &raquo;, *undefined*).
        1. Set _opt_.[[kf]] to _kf_.
        1. Let _kn_ be ? GetOption(_options_, *"numeric"*, ~boolean~, ~empty~, *undefined*).
        1. If _kn_ is not *undefined*, set _kn_ to ! ToString(_kn_).
        1. Set _opt_.[[kn]] to _kn_.
        1. Let _numberingSystem_ be ? GetOption(_options_, *"numberingSystem"*, ~string~, ~empty~, *undefined*).
        1. If _numberingSystem_ is not *undefined*, then
          1. If _numberingSystem_ cannot be matched by the <code>type</code> Unicode locale nonterminal, throw a *RangeError* exception.
        1. Set _opt_.[[nu]] to _numberingSystem_.
        1. Let _r_ be MakeLocaleRecord(_tag_, _opt_, _relevantExtensionKeys_).
        1. Set _locale_.[[Locale]] to _r_.[[locale]].
        1. Set _locale_.[[Calendar]] to _r_.[[ca]].
        1. Set _locale_.[[Collation]] to _r_.[[co]].
        1. <ins>Set _locale_.[[FirstDayOfWeek]] to _r_.[[fw]].</ins>
        1. Set _locale_.[[HourCycle]] to _r_.[[hc]].
        1. If _relevantExtensionKeys_ contains *"kf"*, then
          1. Set _locale_.[[CaseFirst]] to _r_.[[kf]].
        1. If _relevantExtensionKeys_ contains *"kn"*, then
          1. If SameValue(_r_.[[kn]], *"true"*) is *true* or _r_.[[kn]] is the empty String, then
            1. Set _locale_.[[Numeric]] to *true*.
          1. Else,
            1. Set _locale_.[[Numeric]] to *false*.
        1. Set _locale_.[[NumberingSystem]] to _r_.[[nu]].
        1. Return _locale_.
      </emu-alg>
    </emu-clause>
  </emu-clause>

  <emu-clause id="sec-properties-of-intl-locale-constructor">
    <h1>Properties of the Intl.Locale Constructor</h1>

    <p>
      The Intl.Locale constructor has the following properties:
    </p>

    <emu-clause id="sec-intl.locale-internal-slots">
      <h1>Internal slots</h1>

      <p>
        The value of the [[RelevantExtensionKeys]] internal slot is &laquo; *"ca"*, *"co"*,<ins> *"fw"*,</ins> *"hc"*, *"kf"*, *"kn"*, *"nu"* &raquo;. If %Intl.Collator%.[[RelevantExtensionKeys]] does not contain *"kf"*, then remove *"kf"* from %Intl.Locale%.[[RelevantExtensionKeys]]. If %Intl.Collator%.[[RelevantExtensionKeys]] does not contain *"kn"*, then remove *"kn"* from %Intl.Locale%.[[RelevantExtensionKeys]].
      </p>
    </emu-clause>
  </emu-clause>

  <emu-clause id="sec-properties-of-intl-locale-prototype-object">
    <h1>Properties of the Intl.Locale Prototype Object</h1>

    <ins class="block">
    <emu-clause id="sec-Intl.Locale.prototype.firstDayOfWeek">
      <h1>get Intl.Locale.prototype.firstDayOfWeek</h1>
      <p>`Intl.Locale.prototype.firstDayOfWeek` is an accessor property whose set accessor function is *undefined*. Its get accessor function performs the following steps:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Return _loc_.[[FirstDayOfWeek]].
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getCalendars">
      <h1>Intl.Locale.prototype.getCalendars ( )</h1>
      <p>When the `getCalendars` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Return CalendarsOfLocale(_loc_).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getCollations">
      <h1>Intl.Locale.prototype.getCollations ( )</h1>
      <p>When the `getCollations` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Return CollationsOfLocale(_loc_).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getHourCycles">
      <h1>Intl.Locale.prototype.getHourCycles ( )</h1>
      <p>When the `getHourCycles` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Return HourCyclesOfLocale(_loc_).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getNumberingSystems">
      <h1>Intl.Locale.prototype.getNumberingSystems ( )</h1>
      <p>When the `getNumberingSystems` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Return NumberingSystemsOfLocale(_loc_).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getTimeZones">
      <h1>Intl.Locale.prototype.getTimeZones ( )</h1>
      <p>When the `getTimeZones` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Let _region_ be GetLocaleRegion(_loc_.[[Locale]]).
        1. If _region_ is *undefined*, return *undefined*.
        1. Return TimeZonesOfLocale(_loc_).
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getTextInfo">
      <h1>Intl.Locale.prototype.getTextInfo ( )</h1>
      <p>When the `getTextInfo` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Let _info_ be OrdinaryObjectCreate(%Object.prototype%).
        1. Let _dir_ be *"ltr"*.
        1. If LocaleIsRightToLeft(_loc_) is *true*, then
          1. Set _dir_ to *"rtl"*.
        1. Perform ! CreateDataPropertyOrThrow(_info_, *"direction"*, _dir_).
        1. Return _info_.
      </emu-alg>
    </emu-clause>

    <emu-clause id="sec-Intl.Locale.prototype.getWeekInfo">
      <h1>Intl.Locale.prototype.getWeekInfo ( )</h1>
      <p>When the `getWeekInfo` method is called, the following steps are taken:</p>
      <emu-alg>
        1. Let _loc_ be the *this* value.
        1. Perform ? RequireInternalSlot(_loc_, [[InitializedLocale]]).
        1. Let _info_ be OrdinaryObjectCreate(%Object.prototype%).
        1. Let _wi_ be WeekInfoOfLocale(_loc_).
        1. Let _we_ be CreateArrayFromList(_wi_.[[Weekend]]).
        1. Perform ! CreateDataPropertyOrThrow(_info_, *"firstDay"*, _wi_.[[FirstDay]]).
        1. Perform ! CreateDataPropertyOrThrow(_info_, *"weekend"*, _we_).
        1. Return _info_.
      </emu-alg>
    </emu-clause>
    </ins>
  </emu-clause>

  <emu-clause id="sec-properties-of-intl-locale-instances">
    <h1>Properties of Intl.Locale Instances</h1>

    <p>
      Intl.Locale instances are ordinary objects that inherit properties from %Intl.Locale.prototype%.
    </p>

    <p>
      Intl.Locale instances have an [[InitializedLocale]] internal slot.
    </p>

    <p>
      Intl.Locale instances also have several internal slots that are computed by the constructor:
    </p>

    <ul>
      <li>[[Locale]] is a String value with the language tag of the locale whose localization is used for formatting.</li>
      <li>[[Calendar]] is a String value that is a syntactically valid type value as given in <a href="https://unicode.org/reports/tr35/#Unicode_locale_identifier">Unicode Technical Standard #35 Part 1 Core, Section 3.2 Unicode Locale Identifier</a>, or is *undefined*.</li>
      <li>[[Collation]] is a String value that is a syntactically valid type value as given in <a href="https://unicode.org/reports/tr35/#Unicode_locale_identifier">Unicode Technical Standard #35 Part 1 Core, Section 3.2 Unicode Locale Identifier</a>, or is *undefined*.</li>
      <li><ins>[[FirstDayOfWeek]] is a String value that is a syntactically valid type value as given in <a href="https://unicode.org/reports/tr35/#Unicode_locale_identifier">Unicode Technical Standard #35 Part 1 Core, Section 3.2 Unicode Locale Identifier</a>, or is *undefined*.</ins></li>
      <li>[[HourCycle]] is a String value that is a syntactically valid type value as given in <a href="https://unicode.org/reports/tr35/#Unicode_locale_identifier">Unicode Technical Standard #35 Part 1 Core, Section 3.2 Unicode Locale Identifier</a>, or is *undefined*.</li>
      <li>[[NumberingSystem]] is a String value that is a syntactically valid type value as given in <a href="https://unicode.org/reports/tr35/#Unicode_locale_identifier">Unicode Technical Standard #35 Part 1 Core, Section 3.2 Unicode Locale Identifier</a>, or is *undefined*.</li>
      <li>[[CaseFirst]] is a String value that is a syntactically valid type value as given in <a href="https://unicode.org/reports/tr35/#Unicode_locale_identifier">Unicode Technical Standard #35 Part 1 Core, Section 3.2 Unicode Locale Identifier</a>, or is *undefined*. This internal slot only exists if the [[RelevantExtensionKeys]] internal slot of %Intl.Locale% contains *"kf"*.</li>
      <li>[[Numeric]] is a Boolean value specifying whether numeric sorting is used by the locale, or is *undefined*. This internal slot only exists if the [[RelevantExtensionKeys]] internal slot of %Intl.Locale% contains *"kn"*.</li>
    </ul>
  </emu-clause>
</emu-clause>