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spec.emu
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spec.emu
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<!doctype html>
<meta charset="utf8">
<pre class="metadata">
title: Intl.DurationFormat
stage: 3
location: https://tc39.es/proposal-intl-duration-format/
contributors: Ujjwal Sharma, Younies Mahmoud
</pre>
<emu-biblio href="./biblio.json"></emu-biblio>
<emu-clause id="durationformat-objects">
<h1>DurationFormat Objects</h1>
<emu-clause id="sec-intl-durationformat-abstracts">
<h1>Abstract Operations for DurationFormat Objects</h1>
<emu-clause id="sec-duration-records">
<h1>Duration Records</h1>
<p>A <dfn variants="Duration Records">Duration Record</dfn> is a Record value used to represent a Duration.</p>
<p>Duration Records have the fields in <emu-xref href="#table-duration-record-fields"></emu-xref></p>
<emu-table id="table-duration-record-fields" caption="Duration Record Fields">
<table class="real-table">
<tr>
<th>Field</th>
<th>Meaning</th>
</tr>
<tr>
<td>[[Years]]</td>
<td>
The number of years in the duration.
</td>
</tr>
<tr>
<td>[[Months]]</td>
<td>
The number of months in the duration.
</td>
</tr>
<tr>
<td>[[Weeks]]</td>
<td>
The number of weeks in the duration.
</td>
</tr>
<tr>
<td>[[Days]]</td>
<td>
The number of days in the duration.
</td>
</tr>
<tr>
<td>[[Hours]]</td>
<td>
The number of hours in the duration.
</td>
</tr>
<tr>
<td>[[Minutes]]</td>
<td>
The number of minutes in the duration.
</td>
</tr>
<tr>
<td>[[Seconds]]</td>
<td>
The number of seconds in the duration.
</td>
</tr>
<tr>
<td>[[Milliseconds]]</td>
<td>
The number of milliseconds in the duration.
</td>
</tr>
<tr>
<td>[[Microseconds]]</td>
<td>
The number of microseconds in the duration.
</td>
</tr>
<tr>
<td>[[Nanoseconds]]</td>
<td>
The number of nanoseconds in the duration.
</td>
</tr>
</table>
</emu-table>
</emu-clause>
<emu-clause id="sec-tointegerifintegral" oldids="sec-tointegerwithoutrounding" type="abstract operation">
<h1>
ToIntegerIfIntegral (
_argument_: an ECMAScript language value,
): either a normal completion containing an integer, or an abrupt completion
</h1>
<dl class="header">
<dt>description</dt>
<dd>It converts _argument_ to an integer representing its Number value, or throws a *RangeError* when that value is not <emu-xref href="#integral-number">integral</emu-xref>.</dd>
</dl>
<emu-alg>
1. Let _number_ be ? ToNumber(_argument_).
1. If IsIntegralNumber(_number_) is *false*, throw a *RangeError* exception.
1. Return ℝ(_number_).
</emu-alg>
</emu-clause>
<emu-clause id="sec-todurationrecord" type="abstract operation">
<h1>
ToDurationRecord (
_input_: an ECMAScript language value
): either a normal completion containing a Duration Record, or an abrupt completion
</h1>
<dl class="header">
<dt>description</dt>
<dd>It converts a given object that represents a Duration into a Duration Record.</dd>
</dl>
<emu-alg>
1. If Type(_input_) is not Object, then
1. If Type(_input_) is String, throw a *RangeError* exception.
1. Throw a *TypeError* exception.
1. Let _result_ be a new Duration Record with each field set to 0.
1. Let _days_ be ? Get(_input_, *"days"*).
1. If _days_ is not *undefined*, set _result_.[[Days]] to ? ToIntegerIfIntegral(_days_).
1. Let _hours_ be ? Get(_input_, *"hours"*).
1. If _hours_ is not *undefined*, set _result_.[[Hours]] to ? ToIntegerIfIntegral(_hours_).
1. Let _microseconds_ be ? Get(_input_, *"microseconds"*).
1. If _microseconds_ is not *undefined*, set _result_.[[Microseconds]] to ? ToIntegerIfIntegral(_microseconds_).
1. Let _milliseconds_ be ? Get(_input_, *"milliseconds"*).
1. If _milliseconds_ is not *undefined*, set _result_.[[Milliseconds]] to ? ToIntegerIfIntegral(_milliseconds_).
1. Let _minutes_ be ? Get(_input_, *"minutes"*).
1. If _minutes_ is not *undefined*, set _result_.[[Minutes]] to ? ToIntegerIfIntegral(_minutes_).
1. Let _months_ be ? Get(_input_, *"months"*).
1. If _months_ is not *undefined*, set _result_.[[Months]] to ? ToIntegerIfIntegral(_months_).
1. Let _nanoseconds_ be ? Get(_input_, *"nanoseconds"*).
1. If _nanoseconds_ is not *undefined*, set _result_.[[Nanoseconds]] to ? ToIntegerIfIntegral(_nanoseconds_).
1. Let _seconds_ be ? Get(_input_, *"seconds"*).
1. If _seconds_ is not *undefined*, set _result_.[[Seconds]] to ? ToIntegerIfIntegral(_seconds_).
1. Let _weeks_ be ? Get(_input_, *"weeks"*).
1. If _weeks_ is not *undefined*, set _result_.[[Weeks]] to ? ToIntegerIfIntegral(_weeks_).
1. Let _years_ be ? Get(_input_, *"years"*).
1. If _years_ is not *undefined*, set _result_.[[Years]] to ? ToIntegerIfIntegral(_years_).
1. If _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, and _nanoseconds_ are all *undefined*, throw a *TypeError* exception.
1. If IsValidDuration( _result_.[[Years]], _result_.[[Months]], _result_.[[Weeks]], _result_.[[Days]], _result_.[[Hours]], _result_.[[Minutes]], _result_.[[Seconds]], _result_.[[Milliseconds]], _result_.[[Microseconds]], _result_.[[Nanoseconds]]) is *false*, then
1. Throw a *RangeError* exception.
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-durationsign" type="abstract operation">
<h1>
DurationSign (
_years_: an integer,
_months_: an integer,
_weeks_: an integer,
_days_: an integer,
_hours_: an integer,
_minutes_: an integer,
_seconds_: an integer,
_milliseconds_: an integer,
_microseconds_: an integer,
_nanoseconds_: an integer,
): -1, 0, or 1
</h1>
<dl class="header">
<dt>description</dt>
<dd>It returns 1 if the most significant non-zero element in its arguments is positive, and -1 if the most significant non-zero element is negative. If all of its arguments are zero, it returns 0.</dd>
</dl>
<emu-alg>
1. For each value _v_ of « _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_ », do
1. If _v_ < 0, return -1.
1. If _v_ > 0, return 1.
1. Return 0.
</emu-alg>
</emu-clause>
<emu-clause id="sec-isvalidduration" type="abstract operation">
<h1>
IsValidDuration (
_years_: an integer,
_months_: an integer,
_weeks_: an integer,
_days_: an integer,
_hours_: an integer,
_minutes_: an integer,
_seconds_: an integer,
_milliseconds_: an integer,
_microseconds_: an integer,
_nanoseconds_: an integer,
): a Boolean
</h1>
<dl class="header">
<dt>description</dt>
<dd>It returns *true* if its arguments form valid input from which to construct a Duration Record, and *false* otherwise.</dd>
</dl>
<emu-alg>
1. Let _sign_ be DurationSign(_years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_).
1. For each value _v_ of « _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_ », do
1. If 𝔽(_v_) is not finite, return *false*.
1. If _v_ < 0 and _sign_ > 0, return *false*.
1. If _v_ > 0 and _sign_ < 0, return *false*.
1. If abs(_years_) ≥ 2<sup>32</sup>, return *false*.
1. If abs(_months_) ≥ 2<sup>32</sup>, return *false*.
1. If abs(_weeks_) ≥ 2<sup>32</sup>, return *false*.
1. Let _normalizedSeconds_ be _days_ × 86,400 + _hours_ × 3600 + _minutes_ × 60 + _seconds_ + ℝ(𝔽(_milliseconds_)) × 10<sup>-3</sup> + ℝ(𝔽(_microseconds_)) × 10<sup>-6</sup> + ℝ(𝔽(_nanoseconds_)) × 10<sup>-9</sup>.
1. NOTE: The above step cannot be implemented directly using floating-point arithmetic. Multiplying by 10<sup>-3</sup>, 10<sup>-6</sup>, and 10<sup>-9</sup> respectively may be imprecise when _milliseconds_, _microseconds_, or _nanoseconds_ is an unsafe integer. This multiplication can be implemented in C++ with an implementation of `std::remquo()` with sufficient bits in the quotient. String manipulation will also give an exact result, since the multiplication is by a power of 10.
1. If abs(_normalizedSeconds_) ≥ 2<sup>53</sup>, return *false*.
1. Return *true*.
</emu-alg>
<emu-note>The abstract operations ToIntegerIfIntegral, ToDurationRecord, DurationSign, and IsValidDuration take the same parameters as the abstract operations of the same name in the Temporal proposal's specification, and will be removed in favor of those abstract operations if the Temporal proposal becomes part of ECMA-402 before this proposal does.</emu-note>
</emu-clause>
<emu-clause id="sec-getdurationunitoptions" type="abstract operation">
<h1>
GetDurationUnitOptions (
_unit_: a String,
_options_: an Object,
_baseStyle_: a String,
_stylesList_: a List of Strings,
_digitalBase_: a String,
_prevStyle_: a String,
_twoDigitHours_: a Boolean,
): either a normal completion containing a Record with [[Style]] and [[Display]] fields, or an abrupt completion
</h1>
<dl class="header">
<dt>description</dt>
<dd>It extracts the relevant options for any given _unit_ from an Object and returns them as a Record.</dd>
</dl>
<emu-alg>
1. Let _style_ be ? GetOption(_options_, _unit_, ~string~, _stylesList_, *undefined*).
1. Let _displayDefault_ be *"always"*.
1. If _style_ is *undefined*, then
1. If _baseStyle_ is *"digital"*, then
1. If _unit_ is not one of *"hours"*, *"minutes"*, or *"seconds"*, then
1. Set _displayDefault_ to *"auto"*.
1. Set _style_ to _digitalBase_.
1. Else,
1. If _prevStyle_ is *"fractional"*, *"numeric"* or *"2-digit"*, then
1. If _unit_ is not one of *"minutes"* or *"seconds"*, then
1. Set _displayDefault_ to *"auto"*.
1. Set _style_ to *"numeric"*.
1. Else,
1. Set _displayDefault_ to *"auto"*.
1. Set _style_ to _baseStyle_.
1. If _style_ is *"numeric"*, then
1. If _unit_ is one of *"milliseconds"*, *"microseconds"*, or *"nanoseconds"*, then
1. Set _style_ to *"fractional"*.
1. Set _displayDefault_ to *"auto"*.
1. Let _displayField_ be the string-concatenation of _unit_ and *"Display"*.
1. Let _display_ be ? GetOption(_options_, _displayField_, ~string~, « *"auto"*, *"always"* », _displayDefault_).
1. If _display_ is *"always"* and _style_ is *"fractional"*, then
1. Throw a *RangeError* exception.
1. If _prevStyle_ is *"fractional"*, then
1. If _style_ is not *"fractional"*, then
1. Throw a *RangeError* exception.
1. If _prevStyle_ is *"numeric"* or *"2-digit"*, then
1. If _style_ is not *"fractional"*, *"numeric"* or *"2-digit"*, then
1. Throw a *RangeError* exception.
1. If _unit_ is *"minutes"* or *"seconds"*, then
1. Set _style_ to *"2-digit"*.
1. If _unit_ is *"hours"* and _twoDigitHours_ is *true*, then
1. Set _style_ to *"2-digit"*.
1. Return the Record {
[[Style]]: _style_,
[[Display]]: _display_
}.
</emu-alg>
</emu-clause>
<emu-clause id="sec-addfractionaldigits" type="abstract operation">
<h1>
AddFractionalDigits (
_durationFormat_: a DurationFormat Object,
_duration_: a Duration Record,
): a mathematical value
</h1>
<dl class="header">
<dt>description</dt>
<dd>It computes the sum of all values in _durationFormat_ units with *"fractional"* style, expressed as a fraction of the smallest unit of _durationFormat_ that does not use *"fractional"* style.</dd>
</dl>
<emu-alg>
1. Let _result_ be 0.
1. Let _exponent_ be 3.
1. For each row of <emu-xref href="#table-partition-duration-format-pattern"></emu-xref>, except the header row, in table order, do
1. Let _style_ be the value of _durationFormat_'s internal slot whose name is the Style Slot value of the current row.
1. If _style_ is *"fractional"*, then
1. Assert: The Unit value of the current row is *"milliseconds"*, *"microseconds"*, or *"nanoseconds"*.
1. Let _value_ be the value of _duration_'s field whose name is the Value Field value of the current row.
1. Set _value_ to _value_ / 10<sup>_exponent_</sup>.
1. Set _result_ to _result_ + _value_.
1. Set _exponent_ to _exponent_ + 3.
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-nextunitfractional" type="abstract operation">
<h1>
NextUnitFractional (
_durationFormat_: a DurationFormat Object,
_unit_: a String,
): a Boolean
</h1>
<dl class="header">
<dt>description</dt>
<dd>It returns *true* if the next smallest unit uses the *"fractional"* style.</dd>
</dl>
<emu-alg>
1. Assert: _unit_ is *"seconds"*, *"milliseconds"*, or *"microseconds"*.
1. If _unit_ is *"seconds"* and _durationFormat_.[[MillisecondsStyle]] is *"fractional"*, return *true*.
1. Else if _unit_ is *"milliseconds"* and _durationFormat_.[[MicrosecondsStyle]] is *"fractional"*, return *true*.
1. Else if _unit_ is *"microseconds"* and _durationFormat_.[[NanosecondsStyle]] is *"fractional"*, return *true*.
1. Return *false*.
</emu-alg>
</emu-clause>
<emu-clause id="sec-formatnumerichours" type="abstract operation">
<h1>
FormatNumericHours (
_durationFormat_: a DurationFormat object,
_hoursValue_: an integer,
_signDisplayed_: a Boolean,
) : a List of Records
</h1>
<dl class="header">
<dt>description</dt>
<dd>It creates a List of Records containing the formatted parts of _hoursValue_ interpreted as the value of a Duration Record's [[Hours]] field according to the effective locale and the formatting options of _durationFormat_.</dd>
</dl>
<emu-alg>
1. Let _hoursStyle_ be _durationFormat_.[[HoursStyle]].
1. Assert: _hoursStyle_ is *"numeric"* or _hoursStyle_ is *"2-digit"*.
1. Let _result_ be a new empty List.
1. Let _nfOpts_ be OrdinaryObjectCreate(*null*).
1. Let _numberingSystem_ be _durationFormat_.[[NumberingSystem]].
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"numberingSystem"*, _numberingSystem_).
1. If _hoursStyle_ is *"2-digit"*, then
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"minimumIntegerDigits"*, *2*<sub>𝔽</sub>).
1. If _signDisplayed_ is *false*, then
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"signDisplay"*, *"never"*).
1. Let _nf_ be ! Construct(%NumberFormat%, « _durationFormat_.[[Locale]], _nfOpts_ »).
1. Let _hoursParts_ be ! PartitionNumberPattern(_nf_, _hoursValue_).
1. For each Record { [[Type]], [[Value]] } _part_ of _hoursParts_, do
1. Append the Record { [[Type]]: _part_.[[Type]], [[Value]]: _part_.[[Value]], [[Unit]]: *"hour"* } to _result_.
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-formatnumericminutes" type="abstract operation">
<h1>
FormatNumericMinutes (
_durationFormat_: a DurationFormat Object,
_minutesValue_: an integer,
_hoursDisplayed_: a Boolean,
_signDisplayed_: a Boolean,
) : a List of Records
</h1>
<dl class="header">
<dt>description</dt>
<dd>It creates a List of Records containing the formatted parts of _minutesValue_ interpreted as the value of a Duration Record's [[Minutes]] field according to the effective locale and the formatting options of _durationFormat_.</dd>
</dl>
<emu-alg>
1. Let _result_ be a new empty List.
1. If _hoursDisplayed_ is *true*, then
1. Let _separator_ be _durationFormat_.[[DigitalFormat]].[[HoursMinutesSeparator]].
1. Append the Record { [[Type]]: *"literal"*, [[Value]]: _separator_, [[Unit]]: ~empty~ } to _result_.
1. Let _minutesStyle_ be _durationFormat_.[[MinutesStyle]].
1. Assert: _minutesStyle_ is *"numeric"* or _minutesStyle_ is *"2-digit"*.
1. Let _nfOpts_ be OrdinaryObjectCreate(*null*).
1. Let _numberingSystem_ be _durationFormat_.[[NumberingSystem]].
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"numberingSystem"*, _numberingSystem_).
1. If _minutesStyle_ is *"2-digit"*, then
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"minimumIntegerDigits"*, *2*<sub>𝔽</sub>).
1. If _signDisplayed_ is *false*, then
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"signDisplay"*, *"never"*).
1. Let _nf_ be ! Construct(%NumberFormat%, « _durationFormat_.[[Locale]], _nfOpts_ »).
1. Let _minutesParts_ be ! PartitionNumberPattern(_nf_, _minutesValue_).
1. For each Record { [[Type]], [[Value]] } _part_ of _minutesParts_, do
1. Append the Record { [[Type]]: _part_.[[Type]], [[Value]]: _part_.[[Value]], [[Unit]]: *"minute"* } to _result_.
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-formatnumericseconds" type="abstract operation">
<h1>
FormatNumericSeconds (
_durationFormat_: a DurationFormat Object,
_secondsValue_: an integer,
_minutesDisplayed_ : a Boolean,
_signDisplayed_: a Boolean,
) : a List of Records
</h1>
<dl class="header">
<dt>description</dt>
<dd>It creates a List of Records containing the formatted parts of _secondsValue_ interpreted as the value of a Duration Record's [[Seconds]] field according to the effective locale and the formatting options of _durationFormat_.</dd>
</dl>
<emu-alg>
1. Let _secondsStyle_ be _durationFormat_.[[SecondsStyle]].
1. Assert: _secondsStyle_ is *"numeric"* or _secondsStyle_ is *"2-digit"*.
1. Let _result_ be a new empty List.
1. If _minutesDisplayed_ is *true*, then
1. Let _separator_ be _durationFormat_.[[DigitalFormat]].[[MinutesSecondsSeparator]].
1. Append the Record { [[Type]]: *"literal"*, [[Value]]: _separator_, [[Unit]]: ~empty~ } to _result_.
1. Let _nfOpts_ be OrdinaryObjectCreate(*null*).
1. Let _numberingSystem_ be _durationFormat_.[[NumberingSystem]].
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"numberingSystem"*, _numberingSystem_).
1. If _secondsStyle_ is *"2-digit"*, then
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"minimumIntegerDigits"*, *2*<sub>𝔽</sub>).
1. If _signDisplayed_ is *false*, then
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"signDisplay"*, *"never"*).
1. Let _nf_ be ! Construct(%NumberFormat%, « _durationFormat_.[[Locale]], _nfOpts_ »).
1. If _durationFormat_.[[FractionalDigits]] is *undefined*, then
1. Let _maximumFractionDigits_ be *9*<sub>𝔽</sub>.
1. Let _minimumFractionDigits_ be *+0*<sub>𝔽</sub>.
1. Else,
1. Let _maximumFractionDigits_ be _durationFormat_.[[FractionalDigits]].
1. Let _minimumFractionDigits_ be _durationFormat_.[[FractionalDigits]].
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"maximumFractionDigits"*, _maximumFractionDigits_).
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"minimumFractionDigits"*, _minimumFractionDigits_).
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"roundingMode"*, *"trunc"*).
1. Let _secondsParts_ be ! PartitionNumberPattern(_nf_, _secondsValue_).
1. For each Record { [[Type]], [[Value]] } _part_ of _secondsParts_, do
1. Append the Record { [[Type]]: _part_.[[Type]], [[Value]]: _part_.[[Value]], [[Unit]]: *"second"* } to _result_.
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-formatnumericunits" type="abstract operation">
<h1>
FormatNumericUnits (
_durationFormat_: a DurationFormat Object,
_duration_: a Duration Record,
_firstNumericUnit_: a String,
_signDisplayed_: a Boolean,
): a List of Records
</h1>
<dl class="header">
<dt>description</dt>
<dd>It creates a List of Lists of Records containing the formatted parts of _duration_ that use *"numeric"* or *"2-digit"* style according to the effective locale and the formatting options of _durationFormat_.</dd>
</dl>
<emu-alg>
1. Assert: _firstNumericUnit_ is *"hours"*, *"minutes"*, or *"seconds"*.
1. Let _numericPartsList_ be a new empty List.
1. Let _hoursValue_ be _duration_.[[Hours]].
1. Let _hoursDisplay_ be _durationFormat_.[[HoursDisplay]].
1. Let _minutesValue_ be _duration_.[[Minutes]].
1. Let _minutesDisplay_ be _durationFormat_.[[MinutesDisplay]].
1. Let _secondsValue_ be _duration_.[[Seconds]].
1. If _duration_.[[Milliseconds]] is not 0 or _duration_.[[Microseconds]] is not 0 or _duration_.[[Nanoseconds]] is not 0, then
1. Set _secondsValue_ to _secondsValue_ + AddFractionalDigits(_durationFormat_, _duration_).
1. Let _secondsDisplay_ be _durationFormat_.[[SecondsDisplay]].
1. Let _hoursFormatted_ be *false*.
1. If _firstNumericUnit_ is *"hours"*, then
1. If _hoursValue_ is not 0 or _hoursDisplay_ is not *"auto"*, then
1. Set _hoursFormatted_ to *true*.
1. If _secondsValue_ is not 0 or _secondsDisplay_ is not *"auto"*, then
1. Let _secondsFormatted_ be *true*.
1. Else,
1. Let _secondsFormatted_ be *false*.
1. Let _minutesFormatted_ be *false*.
1. If _firstNumericUnit_ is *"hours"* or _firstNumericUnit_ is *"minutes"*, then
1. If _hoursFormatted_ is *true* and _secondsFormatted_ is *true*, then
1. Set _minutesFormatted_ to *true*.
1. Else if _minutesValue_ is not 0 or _minutesDisplay_ is not *"auto"*, then
1. Set _minutesFormatted_ to *true*.
1. If _hoursFormatted_ is *true*, then
1. Append FormatNumericHours(_durationFormat_, _hoursValue_, _signDisplayed_) to _numericPartsList_.
1. Set _signDisplayed_ to *false*.
1. If _minutesFormatted_ is *true*, then
1. Append FormatNumericMinutes(_durationFormat_, _minutesValue_, _hoursFormatted_, _signDisplayed_) to _numericPartsList_.
1. Set _signDisplayed_ to *false*.
1. If _secondsFormatted_ is *true*, then
1. Append FormatNumericSeconds(_durationFormat_, _secondsValue_, _minutesFormatted_, _signDisplayed_) to _numericPartsList_.
1. Set _signDisplayed_ to *false*.
1. Return _numericPartsList_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-listformatparts" type="abstract operation">
<h1>ListFormatParts (
_durationFormat_: a DurationFormat Object
_partitionedPartsList_: a List of Lists of Records,
): a List
</h1>
<dl class="header">
<dt>description</dt>
<dd>It creates and returns a List with all the corresponding parts according to the effective locale and the formatting options of _durationFormat_.</dd>
</dl>
<emu-alg>
1. Let _lfOpts_ be OrdinaryObjectCreate(*null*).
1. Perform ! CreateDataPropertyOrThrow(_lfOpts_, *"type"*, *"unit"*).
1. Let _listStyle_ be _durationFormat_.[[Style]].
1. If _listStyle_ is *"digital"*, then
1. Set _listStyle_ to *"short"*.
1. Perform ! CreateDataPropertyOrThrow(_lfOpts_, *"style"*, _listStyle_).
1. Let _lf_ be ! Construct(%ListFormat%, « _durationFormat_.[[Locale]], _lfOpts_ »).
1. Let _strings_ be a new empty List.
1. For each element _parts_ of _partitionedPartsList_, do
1. Let _string_ be the empty String.
1. For each Record { [[Type]], [[Value]], [[Unit]] } _part_ in _parts_, do
1. Set _string_ to the string-concatenation of _string_ and _part_.[[Value]].
1. Append _string_ to _strings_.
1. Let _formattedPartsList_ be CreatePartsFromList(_lf_, _strings_).
1. Let _partitionedPartsIndex_ be 0.
1. Let _partitionedLength_ be the number of elements in _partitionedPartsList_.
1. Let _flattenedPartsList_ be a new empty List.
1. For each Record { [[Type]], [[Value]] } _listPart_ in _formattedPartsList_, do
1. If _listPart_.[[Type]] is *"element"*, then
1. Assert: _partitionedPartsIndex_ < _partitionedLength_.
1. Let _parts_ be _partitionedPartsList_[_partitionedPartsIndex_].
1. For each Record { [[Type]], [[Value]], [[Unit]] } _part_ in _parts_, do
1. Append _part_ to _flattenedPartsList_.
1. Set _partitionedPartsIndex_ to _partitionedPartsIndex_ + 1.
1. Else,
1. Assert: _listPart_.[[Type]] is *"literal"*.
1. Append the Record { [[Type]]: *"literal"*, [[Value]]: _listPart_.[[Value]], [[Unit]]: ~empty~ } to _flattenedPartsList_.
1. Return _flattenedPartsList_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-partitiondurationformatpattern" type="abstract operation">
<h1>
PartitionDurationFormatPattern (
_durationFormat_: a DurationFormat,
_duration_: a Duration Record,
): a List
</h1>
<dl class="header">
<dt>description</dt>
<dd>It creates and returns a List with all the corresponding parts according to the effective locale and the formatting options of _durationFormat_.</dd>
</dl>
<emu-alg>
1. Let _result_ be a new empty List.
1. Let _signDisplayed_ be *true*.
1. Let _numericUnitFound_ be *false*.
1. While _numericUnitFound_ is *false*, repeat for each row in <emu-xref href="#table-partition-duration-format-pattern"></emu-xref> in table order, except the header row:
1. Let _value_ be the value of _duration_'s field whose name is the Value Field value of the current row.
1. Let _style_ be the value of _durationFormat_'s internal slot whose name is the Style Slot value of the current row.
1. Let _display_ be the value of _durationFormat_'s internal slot whose name is the Display Slot value of the current row.
1. Let _unit_ be the Unit value of the current row.
1. If _style_ is *"numeric"* or *"2-digit"*, then
1. Append FormatNumericUnits(_durationFormat_, _duration_, _unit_, _signDisplayed_) to _result_.
1. Set _numericUnitFound_ to *true*.
1. Else,
1. Let _nfOpts_ be OrdinaryObjectCreate(*null*).
1. If _unit_ is *"seconds"*, *"milliseconds"*, or *"microseconds"*, then
1. If NextUnitFractional(_durationFormat_, _unit_) is *true*, then
1. Set _value_ to _value_ + AddFractionalDigits(_durationFormat_, _duration_).
1. If _durationFormat_.[[FractionalDigits]] is *undefined*, then
1. Let _maximumFractionDigits_ be *9*<sub>𝔽</sub>.
1. Let _minimumFractionDigits_ be *+0*<sub>𝔽</sub>.
1. Else,
1. Let _maximumFractionDigits_ be _durationFormat_.[[FractionalDigits]].
1. Let _minimumFractionDigits_ be _durationFormat_.[[FractionalDigits]].
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"maximumFractionDigits"*, _maximumFractionDigits_).
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"minimumFractionDigits"*, _minimumFractionDigits_).
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"roundingMode"*, *"trunc"*).
1. Set _numericUnitFound_ to *true*.
1. If _value_ is not 0 or _display_ is not *"auto"*, then
1. Let _numberingSystem_ be _durationFormat_.[[NumberingSystem]].
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"numberingSystem"*, _numberingSystem_).
1. If _signDisplayed_ is *true*, then
1. Set _signDisplayed_ to *false*.
1. If _value_ is 0 and DurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]) is -1, then
1. Set _value_ to ~negative-zero~.
1. Else,
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"signDisplay"*, *"never"*).
1. Let _numberFormatUnit_ be the NumberFormat Unit value of the current row.
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"style"*, *"unit"*).
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"unit"*, _numberFormatUnit_).
1. Perform ! CreateDataPropertyOrThrow(_nfOpts_, *"unitDisplay"*, _style_).
1. Let _nf_ be ! Construct(%NumberFormat%, « _durationFormat_.[[Locale]], _nfOpts_ »).
1. Let _parts_ be ! PartitionNumberPattern(_nf_, _value_).
1. Let _list_ be a new empty List.
1. For each Record { [[Type]], [[Value]] } _part_ of _parts_, do
1. Append the Record { [[Type]]: _part_.[[Type]], [[Value]]: _part_.[[Value]], [[Unit]]: _numberFormatUnit_ } to _list_.
1. Append _list_ to _result_.
1. Return ListFormatParts(_durationFormat_, _result_).
</emu-alg>
<emu-table id="table-partition-duration-format-pattern">
<emu-caption>DurationFormat instance internal slots and properties relevant to PartitionDurationFormatPattern</emu-caption>
<table class="real-table">
<thead>
<tr>
<th>Value Field</th>
<th>Style Slot</th>
<th>Display Slot</th>
<th>Unit</th>
<th>NumberFormat Unit</th>
</tr>
</thead>
<tr>
<td>[[Years]]</td>
<td>[[YearsStyle]]</td>
<td>[[YearsDisplay]]</td>
<td>*"years"*</td>
<td>*"year"*</td>
</tr>
<tr>
<td>[[Months]]</td>
<td>[[MonthsStyle]]</td>
<td>[[MonthsDisplay]]</td>
<td>*"months"*</td>
<td>*"month"*</td>
</tr>
<tr>
<td>[[Weeks]]</td>
<td>[[WeeksStyle]]</td>
<td>[[WeeksDisplay]]</td>
<td>*"weeks"*</td>
<td>*"week"*</td>
</tr>
<tr>
<td>[[Days]]</td>
<td>[[DaysStyle]]</td>
<td>[[DaysDisplay]]</td>
<td>*"days"*</td>
<td>*"day"*</td>
</tr>
<tr>
<td>[[Hours]]</td>
<td>[[HoursStyle]]</td>
<td>[[HoursDisplay]]</td>
<td>*"hours"*</td>
<td>*"hour"*</td>
</tr>
<tr>
<td>[[Minutes]]</td>
<td>[[MinutesStyle]]</td>
<td>[[MinutesDisplay]]</td>
<td>*"minutes"*</td>
<td>*"minute"*</td>
</tr>
<tr>
<td>[[Seconds]]</td>
<td>[[SecondsStyle]]</td>
<td>[[SecondsDisplay]]</td>
<td>*"seconds"*</td>
<td>*"second"*</td>
</tr>
<tr>
<td>[[Milliseconds]]</td>
<td>[[MillisecondsStyle]]</td>
<td>[[MillisecondsDisplay]]</td>
<td>*"milliseconds"*</td>
<td>*"millisecond"*</td>
</tr>
<tr>
<td>[[Microseconds]]</td>
<td>[[MicrosecondsStyle]]</td>
<td>[[MicrosecondsDisplay]]</td>
<td>*"microseconds"*</td>
<td>*"microsecond"*</td>
</tr>
<tr>
<td>[[Nanoseconds]]</td>
<td>[[NanosecondsStyle]]</td>
<td>[[NanosecondsDisplay]]</td>
<td>*"nanoseconds"*</td>
<td>*"nanosecond"*</td>
</tr>
</table>
</emu-table>
</emu-clause>
</emu-clause>
<emu-clause id="sec-intl-durationformat-constructor">
<h1>The Intl.DurationFormat Constructor</h1>
<p>The DurationFormat constructor is the <dfn>%DurationFormat%</dfn> intrinsic object and a standard built-in property of the Intl object. Behaviour common to all service constructor properties of the Intl object is specified in <emu-xref href="#sec-internal-slots"></emu-xref>.</p>
<emu-clause id="sec-Intl.DurationFormat">
<h1>Intl.DurationFormat ( [ _locales_ [ , _options_ ] ] )</h1>
<p>When the `Intl.DurationFormat` function is called with optional arguments _locales_ and _options_, the following steps are taken:</p>
<emu-alg>
1. If NewTarget is *undefined*, throw a *TypeError* exception.
1. Let _durationFormat_ be ? OrdinaryCreateFromConstructor(NewTarget, *"%DurationFormatPrototype%"*, « [[InitializedDurationFormat]], [[Locale]], [[DataLocale]], [[NumberingSystem]], [[Style]], [[YearsStyle]], [[YearsDisplay]], [[MonthsStyle]], [[MonthsDisplay]], [[WeeksStyle]], [[WeeksDisplay]], [[DaysStyle]], [[DaysDisplay]], [[HoursStyle]], [[HoursDisplay]], [[MinutesStyle]], [[MinutesDisplay]], [[SecondsStyle]], [[SecondsDisplay]], [[MillisecondsStyle]], [[MillisecondsDisplay]], [[MicrosecondsStyle]], [[MicrosecondsDisplay]], [[NanosecondsStyle]], [[NanosecondsDisplay]], [[HoursMinutesSeparator]], [[MinutesSecondsSeparator]], [[FractionalDigits]], [[TwoDigitHours]] »).
1. Let _requestedLocales_ be ? CanonicalizeLocaleList(_locales_).
1. Let _options_ be ? GetOptionsObject(_options_).
1. Let _matcher_ be ? GetOption(_options_, *"localeMatcher"*, ~string~, « *"lookup"*, *"best fit"* », *"best fit"*).
1. Let _numberingSystem_ be ? GetOption(_options_, *"numberingSystem"*, ~string~, *undefined*, *undefined*).
1. If _numberingSystem_ is not *undefined*, then
1. If _numberingSystem_ does not match the Unicode Locale Identifier `type` nonterminal, throw a *RangeError* exception.
1. Let _opt_ be the Record { [[localeMatcher]]: _matcher_, [[nu]]: _numberingSystem_ }.
1. Let _r_ be ResolveLocale(%DurationFormat%.[[AvailableLocales]], _requestedLocales_, _opt_, %DurationFormat%.[[RelevantExtensionKeys]], %DurationFormat%.[[LocaleData]]).
1. Let _locale_ be r.[[locale]].
1. Set _durationFormat_.[[Locale]] to _locale_.
1. Set _durationFormat_.[[DataLocale]] to _r_.[[dataLocale]].
1. Let _dataLocale_ be _durationFormat_.[[DataLocale]].
1. Let _dataLocaleData_ be _durationFormat_.[[LocaleData]].[[<_dataLocale_>]].
1. Let _digitalFormat_ be _dataLocaleData_.[[DigitalFormat]].
1. Let _twoDigitHours_ be _digitalFormat_.[[TwoDigitHours]].
1. Set _durationFormat_.[[TwoDigitHours]] to _twoDigitHours_.
1. Let _hoursMinutesSeparator_ be _digitalFormat_.[[HoursMinutesSeparator]].
1. Set _durationFormat_.[[HoursMinutesSeparator]] to _hoursMinutesSeparator_.
1. Let _minutesSecondsSeparator_ be _digitalFormat_.[[MinutesSecondsSeparator]].
1. Set _durationFormat_.[[MinutesSecondsSeparator]] to _minutesSecondsSeparator_.
1. Set _durationFormat_.[[NumberingSystem]] to _r_.[[nu]].
1. Let _style_ be ? GetOption(_options_, *"style"*, ~string~, « *"long"*, *"short"*, *"narrow"*, *"digital"* », *"short"*).
1. Set _durationFormat_.[[Style]] to _style_.
1. Let _prevStyle_ be the empty String.
1. For each row of <emu-xref href="#table-durationformat"></emu-xref>, except the header row, in table order, do
1. Let _styleSlot_ be the Style Slot value of the current row.
1. Let _displaySlot_ be the Display Slot value of the current row.
1. Let _unit_ be the Unit value of the current row.
1. Let _valueList_ be the Values value of the current row.
1. Let _digitalBase_ be the Digital Default value of the current row.
1. Let _unitOptions_ be ? GetDurationUnitOptions(_unit_, _options_, _style_, _valueList_, _digitalBase_, _prevStyle_, _twoDigitHours_).
1. Set the value of the _styleSlot_ slot of _durationFormat_ to _unitOptions_.[[Style]].
1. Set the value of the _displaySlot_ slot of _durationFormat_ to _unitOptions_.[[Display]].
1. If _unit_ is one of *"hours"*, *"minutes"*, *"seconds"*, *"milliseconds"*, or *"microseconds"*, then
1. Set _prevStyle_ to _unitOptions_.[[Style]].
1. Set _durationFormat_.[[FractionalDigits]] to ? GetNumberOption(_options_, *"fractionalDigits"*, 0, 9, *undefined*).
1. Return _durationFormat_.
</emu-alg>
<emu-table id="table-durationformat">
<emu-caption>Internal slots and property names of DurationFormat instances relevant to Intl.DurationFormat constructor</emu-caption>
<table class="real-table">
<thead>
<tr>
<th>Style Slot</th>
<th>Display Slot</th>
<th>Unit</th>
<th>Values</th>
<th>Digital Default</th>
</tr>
</thead>
<tr>
<td>[[YearsStyle]]</td>
<td>[[YearsDisplay]]</td>
<td>*"years"*</td>
<td>« *"long"*, *"short"*, *"narrow"* »</td>
<td>*"short"*</td>
</tr>
<tr>
<td>[[MonthsStyle]]</td>
<td>[[MonthsDisplay]]</td>
<td>*"months"*</td>
<td>« *"long"*, *"short"*, *"narrow"* »</td>
<td>*"short"*</td>
</tr>
<tr>
<td>[[WeeksStyle]]</td>
<td>[[WeeksDisplay]]</td>
<td>*"weeks"*</td>
<td>« *"long"*, *"short"*, *"narrow"* »</td>
<td>*"short"*</td>
</tr>
<tr>
<td>[[DaysStyle]]</td>
<td>[[DaysDisplay]]</td>
<td>*"days"*</td>
<td>« *"long"*, *"short"*, *"narrow"* »</td>
<td>*"short"*</td>
</tr>
<tr>
<td>[[HoursStyle]]</td>
<td>[[HoursDisplay]]</td>
<td>*"hours"*</td>
<td>« *"long"*, *"short"*, *"narrow"*, <br/>*"numeric"*, *"2-digit"* »</td>
<td>*"numeric"*</td>
</tr>
<tr>
<td>[[MinutesStyle]]</td>
<td>[[MinutesDisplay]]</td>
<td>*"minutes"*</td>
<td>« *"long"*, *"short"*, *"narrow"*, <br/>*"numeric"*, *"2-digit"* »</td>
<td>*"numeric"*</td>
</tr>
<tr>
<td>[[SecondsStyle]]</td>
<td>[[SecondsDisplay]]</td>
<td>*"seconds"*</td>
<td>« *"long"*, *"short"*, *"narrow"*, <br/>*"numeric"*, *"2-digit"* »</td>
<td>*"numeric"*</td>
</tr>
<tr>
<td>[[MillisecondsStyle]]</td>
<td>[[MillisecondsDisplay]]</td>
<td>*"milliseconds"*</td>
<td>« *"long"*, *"short"*, *"narrow"*, <br/>*"numeric"* »</td>
<td>*"numeric"*</td>
</tr>
<tr>
<td>[[MicrosecondsStyle]]</td>
<td>[[MicrosecondsDisplay]]</td>
<td>*"microseconds"*</td>
<td>« *"long"*, *"short"*, *"narrow"*, <br/>*"numeric"* »</td>
<td>*"numeric"*</td>
</tr>
<tr>
<td>[[NanosecondsStyle]]</td>
<td>[[NanosecondsDisplay]]</td>
<td>*"nanoseconds"*</td>
<td>« *"long"*, *"short"*, *"narrow"*, <br/>*"numeric"* »</td>
<td>*"numeric"*</td>
</tr>
</table>
</emu-table>
</emu-clause>
</emu-clause>
<emu-clause id="sec-properties-of-intl-durationformat-constructor">
<h1>Properties of the Intl.DurationFormat Constructor</h1>
<p>The Intl.DurationFormat constructor has the following properties:</p>
<emu-clause id="sec-Intl.DurationFormat.prototype">
<h1>Intl.DurationFormat.prototype</h1>
<p>The value of `Intl.DurationFormat.prototype` is %DurationFormatPrototype%.</p>
<p>This property has the attributes { [[Writable]]: *false*, [[Enumerable]]: *false*, [[Configurable]]: *false* }.</p>
</emu-clause>
<emu-clause id="sec-Intl.DurationFormat.supportedLocalesOf">
<h1>Intl.DurationFormat.supportedLocalesOf ( _locales_ [ , _options_ ] )</h1>
<p>When the `supportedLocalesOf` method is called with arguments _locales_ and _options_, the following steps are taken:</p>
<emu-alg>
1. Let _availableLocales_ be %DurationFormat%.[[AvailableLocales]].
1. Let _requestedLocales_ be ? CanonicalizeLocaleList(_locales_).
1. Return ? SupportedLocales(_availableLocales_, _requestedLocales_, _options_).
</emu-alg>
</emu-clause>
<emu-clause id="sec-Intl.DurationFormat-internal-slots">
<h1>Internal slots</h1>
<p>The value of the [[AvailableLocales]] internal slot is implementation defined within the constraints described in <emu-xref href="#sec-internal-slots"></emu-xref>.</p>
<p>The value of the [[RelevantExtensionKeys]] internal slot is « *"nu"* ».</p>
<p>The value of the [[LocaleData]] internal slot is implementation defined within the constraints described in <emu-xref href="#sec-internal-slots"></emu-xref> and the following additional constraints for all locale values _locale_:</p>
<ul>
<li>[[LocaleData]].[[<_locale_>]].[[nu]] must be a List as specified in <emu-xref href="#sec-intl.numberformat-internal-slots"></emu-xref>.</li>
<li>[[LocaleData]].[[<_locale_>]].[[DigitalFormat]] must be a Record with keys corresponding to each numbering system available for the given locale, with Record values containing the following fields:
<ul><li>[[HourMinutesSeparator]] is a String value that is the appropriate separator between hours and minutes for that combination of locale, numbering system, and unit when using *"numeric"* or "2-digit" styles</li>
<li>[[MinutesSecondsSeparator]] is a String value that is the appropriate separator between minutes and seconds for that combination of locale, numbering system, and unit when using *"numeric"* or *"2-digit"* styles.</li>
<li>[[TwoDigitHours]] is a Boolean value indicating whether hours are always displayed using two digits when the *"numeric"* style is used.</li>
</ul>
</li>
</ul>
<emu-note>It is recommended that implementations use the locale data provided by the Common Locale Data Repository (available at <a href="http://cldr.unicode.org/">http://cldr.unicode.org/</a>).</emu-note>
</emu-clause>
</emu-clause>
<emu-clause id="sec-properties-of-intl-durationformat-prototype-object">
<h1>Properties of the Intl.DurationFormat Prototype Object</h1>
<p>The Intl.DurationFormat prototype object is itself an ordinary object. <dfn>%DurationFormatPrototype%</dfn> is not an Intl.DurationFormat instance and does not have an [[InitializedDurationFormat]] internal slot or any of the other internal slots of Intl.DurationFormat instance objects.</p>
<emu-clause id="sec-Intl.DurationFormat.prototype.constructor">
<h1>Intl.DurationFormat.prototype.constructor</h1>
<p>The initial value of `Intl.DurationFormat.prototype.constructor` is the intrinsic object %DurationFormat%.</p>
</emu-clause>
<emu-clause id="sec-Intl.DurationFormat.prototype-@@tostringtag">
<h1>Intl.DurationFormat.prototype [ @@toStringTag ]</h1>
<p>The initial value of the @@toStringTag property is the string value *"Intl.DurationFormat"*.</p>
<p>This property has the attributes { [[Writable]]: *false*, [[Enumerable]]: *false*, [[Configurable]]: *true* }.</p>
</emu-clause>
<emu-clause id="sec-Intl.DurationFormat.prototype.format">
<h1>Intl.DurationFormat.prototype.format ( _duration_ )</h1>
<p>When the `format` method is called with an argument _duration_, the following steps are taken:</p>
<emu-alg>
1. Let _df_ be *this* value.
1. Perform ? RequireInternalSlot(_df_, [[InitializedDurationFormat]]).
1. Let _record_ be ? ToDurationRecord(_duration_).
1. Let _parts_ be PartitionDurationFormatPattern(_df_, _record_).
1. Let _result_ be the empty String.
1. For each Record { [[Type]], [[Value]], [[Unit]] } _part_ in _parts_, do
1. Set _result_ to the string-concatenation of _result_ and _part_.[[Value]].
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-Intl.DurationFormat.prototype.formatToParts">
<h1>Intl.DurationFormat.prototype.formatToParts ( _duration_ )</h1>
<p>When the `formatToParts` method is called with an argument _duration_, the following steps are taken:</p>
<emu-alg>
1. Let _df_ be *this* value.
1. Perform ? RequireInternalSlot(_df_, [[InitializedDurationFormat]]).
1. Let _record_ be ? ToDurationRecord(_duration_).
1. Let _parts_ be PartitionDurationFormatPattern(_df_, _record_).
1. Let _result_ be ! ArrayCreate(0).
1. Let _n_ be 0.
1. For each Record { [[Type]], [[Value]], [[Unit]] } _part_ in _parts_, do
1. Let _obj_ be OrdinaryObjectCreate(%ObjectPrototype%).
1. Perform ! CreateDataPropertyOrThrow(_obj_, *"type"*, _part_.[[Type]]).
1. Perform ! CreateDataPropertyOrThrow(_obj_, *"value"*, _part_.[[Value]]).
1. If _part_.[[Unit]] is not ~empty~, perform ! CreateDataPropertyOrThrow(_obj_, *"unit"*, _part_.[[Unit]]).
1. Perform ! CreateDataPropertyOrThrow(_result_, ! ToString(_n_), _obj_).
1. Set _n_ to _n_ + 1.
1. Return _result_.
</emu-alg>
</emu-clause>
<emu-clause id="sec-Intl.DurationFormat.prototype.resolvedOptions">
<h1>Intl.DurationFormat.prototype.resolvedOptions ( )</h1>
<p>This function provides access to the locale and options computed during initialization of the object.</p>
<emu-alg>
1. Let _df_ be the *this* value.
1. Perform ? RequireInternalSlot(_df_, [[InitializedDurationFormat]]).
1. Let _options_ be OrdinaryObjectCreate(%ObjectPrototype%).
1. For each row of <emu-xref href="#table-durationformat-resolvedoptions-properties"></emu-xref>, except the header row, in table order, do
1. Let _p_ be the Property value of the current row.
1. Let _v_ be the value of _df_'s internal slot whose name is the Internal Slot value of the current row.
1. If _p_ is *"fractionalDigits"*, then
1. If _v_ is not *undefined*, set _v_ to 𝔽(_v_).
1. Else,
1. Assert: _v_ is not *undefined*.
1. If _v_ is *"fractional"*, then
1. Assert: The Internal Slot value of the current row is [[MillisecondsStyle]], [[MicrosecondsStyle]], or [[NanosecondsStyle]] .
1. Set _v_ to *"numeric"*.
1. If _v_ is not *undefined*, then
1. Perform ! CreateDataPropertyOrThrow(_options_, _p_, _v_).
1. Return _options_.
</emu-alg>
<emu-table id="table-durationformat-resolvedoptions-properties">
<emu-caption>Resolved Options of DurationFormat Instances</emu-caption>
<table class="real-table">
<thead>
<tr>
<th>Internal Slot</th>
<th>Property</th>
</tr>
</thead>
<tr>
<td>[[Locale]]</td>
<td>*"locale"*</td>
</tr>
<tr>
<td>[[NumberingSystem]]</td>
<td>*"numberingSystem"*</td>
</tr>
<tr>
<td>[[Style]]</td>
<td>*"style"*</td>
</tr>
<tr>
<td>[[YearsStyle]]</td>
<td>*"years"*</td>
</tr>
<tr>
<td>[[YearsDisplay]]</td>
<td>*"yearsDisplay"*</td>
</tr>
<tr>
<td>[[MonthsStyle]]</td>
<td>*"months"*</td>
</tr>
<tr>
<td>[[MonthsDisplay]]</td>
<td>*"monthsDisplay"*</td>
</tr>
<tr>
<td>[[WeeksStyle]]</td>
<td>*"weeks"*</td>
</tr>
<tr>
<td>[[WeeksDisplay]]</td>
<td>*"weeksDisplay"*</td>
</tr>
<tr>
<td>[[DaysStyle]]</td>
<td>*"days"*</td>
</tr>
<tr>
<td>[[DaysDisplay]]</td>
<td>*"daysDisplay"*</td>
</tr>
<tr>
<td>[[HoursStyle]]</td>
<td>*"hours"*</td>
</tr>
<tr>
<td>[[HoursDisplay]]</td>
<td>*"hoursDisplay"*</td>
</tr>