@js-temporal/polyfill/lib/plainyearmonth.ts

Polyfill for Tc39 Stage 3 proposal Temporal (https://github.com/tc39/proposal-temporal)

import * as ES from './ecmascript';
import { MakeIntrinsicClass } from './intrinsicclass';
import { ISO_YEAR, ISO_MONTH, ISO_DAY, CALENDAR, GetSlot } from './slots';
import type { Temporal } from '..';
import { DateTimeFormat } from './intl';
import type { PlainYearMonthParams as Params, PlainYearMonthReturn as Return } from './internaltypes';

const ObjectCreate = Object.create;

export class PlainYearMonth implements Temporal.PlainYearMonth {
  constructor(
    isoYearParam: Params['constructor'][0],
    isoMonthParam: Params['constructor'][1],
    calendarParam: Params['constructor'][2] = ES.GetISO8601Calendar(),
    referenceISODayParam: Params['constructor'][3] = 1
  ) {
    const isoYear = ES.ToIntegerThrowOnInfinity(isoYearParam);
    const isoMonth = ES.ToIntegerThrowOnInfinity(isoMonthParam);
    const calendar = ES.ToTemporalCalendar(calendarParam);
    const referenceISODay = ES.ToIntegerThrowOnInfinity(referenceISODayParam);

    // Note: if the arguments are not passed,
    //       ToIntegerThrowOnInfinity(undefined) will have returned 0, which will
    //       be rejected by RejectISODate in CreateTemporalYearMonthSlots. This
    //       check exists only to improve the error message.
    if (arguments.length < 2) {
      throw new RangeError('missing argument: isoYear and isoMonth are required');
    }

    ES.CreateTemporalYearMonthSlots(this, isoYear, isoMonth, calendar, referenceISODay);
  }
  get year(): Return['year'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarYear(GetSlot(this, CALENDAR), this);
  }
  get month(): Return['month'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarMonth(GetSlot(this, CALENDAR), this);
  }
  get monthCode(): Return['monthCode'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarMonthCode(GetSlot(this, CALENDAR), this);
  }
  get calendar(): Return['calendar'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return GetSlot(this, CALENDAR);
  }
  get era(): Return['era'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarEra(GetSlot(this, CALENDAR), this);
  }
  get eraYear(): Return['eraYear'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarEraYear(GetSlot(this, CALENDAR), this);
  }
  get daysInMonth(): Return['daysInMonth'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarDaysInMonth(GetSlot(this, CALENDAR), this);
  }
  get daysInYear(): Return['daysInYear'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarDaysInYear(GetSlot(this, CALENDAR), this);
  }
  get monthsInYear(): Return['monthsInYear'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarMonthsInYear(GetSlot(this, CALENDAR), this);
  }
  get inLeapYear(): Return['inLeapYear'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.CalendarInLeapYear(GetSlot(this, CALENDAR), this);
  }
  with(temporalYearMonthLike: Params['with'][0], optionsParam: Params['with'][1] = undefined): Return['with'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    if (!ES.IsObject(temporalYearMonthLike)) {
      throw new TypeError('invalid argument');
    }
    ES.RejectObjectWithCalendarOrTimeZone(temporalYearMonthLike);

    const calendar = GetSlot(this, CALENDAR);
    const fieldNames = ES.CalendarFields(calendar, ['month', 'monthCode', 'year'] as const);
    const props = ES.PrepareTemporalFields(temporalYearMonthLike, fieldNames, 'partial');
    if (!props) {
      throw new TypeError('invalid year-month-like');
    }
    let fields = ES.PrepareTemporalFields(this, fieldNames, []);
    fields = ES.CalendarMergeFields(calendar, fields, props);
    fields = ES.PrepareTemporalFields(fields, fieldNames, []);

    const options = ES.GetOptionsObject(optionsParam);

    return ES.CalendarYearMonthFromFields(calendar, fields, options);
  }
  add(temporalDurationLike: Params['add'][0], options: Params['add'][1] = undefined): Return['add'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.AddDurationToOrSubtractDurationFromPlainYearMonth('add', this, temporalDurationLike, options);
  }
  subtract(
    temporalDurationLike: Params['subtract'][0],
    options: Params['subtract'][1] = undefined
  ): Return['subtract'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.AddDurationToOrSubtractDurationFromPlainYearMonth('subtract', this, temporalDurationLike, options);
  }
  until(other: Params['until'][0], options: Params['until'][1] = undefined): Return['until'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.DifferenceTemporalPlainYearMonth('until', this, other, options);
  }
  since(other: Params['since'][0], options: Params['since'][1] = undefined): Return['since'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.DifferenceTemporalPlainYearMonth('since', this, other, options);
  }
  equals(otherParam: Params['equals'][0]): Return['equals'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    const other = ES.ToTemporalYearMonth(otherParam);
    for (const slot of [ISO_YEAR, ISO_MONTH, ISO_DAY]) {
      const val1 = GetSlot(this, slot);
      const val2 = GetSlot(other, slot);
      if (val1 !== val2) return false;
    }
    return ES.CalendarEquals(GetSlot(this, CALENDAR), GetSlot(other, CALENDAR));
  }
  toString(optionsParam: Params['toString'][0] = undefined): string {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    const options = ES.GetOptionsObject(optionsParam);
    const showCalendar = ES.ToShowCalendarOption(options);
    return ES.TemporalYearMonthToString(this, showCalendar);
  }
  toJSON(): Return['toJSON'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return ES.TemporalYearMonthToString(this);
  }
  toLocaleString(
    locales: Params['toLocaleString'][0] = undefined,
    options: Params['toLocaleString'][1] = undefined
  ): string {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return new DateTimeFormat(locales, options).format(this);
  }
  valueOf(): never {
    throw new TypeError('use compare() or equals() to compare Temporal.PlainYearMonth');
  }
  toPlainDate(item: Params['toPlainDate'][0]): Return['toPlainDate'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    if (!ES.IsObject(item)) throw new TypeError('argument should be an object');
    const calendar = GetSlot(this, CALENDAR);

    const receiverFieldNames = ES.CalendarFields(calendar, ['monthCode', 'year'] as const);
    const fields = ES.PrepareTemporalFields(this, receiverFieldNames, []);

    const inputFieldNames = ES.CalendarFields(calendar, ['day'] as const);
    const inputFields = ES.PrepareTemporalFields(item, inputFieldNames, []);
    let mergedFields = ES.CalendarMergeFields(calendar, fields, inputFields);

    // TODO: Use MergeLists abstract operation.
    const mergedFieldNames = [...new Set([...receiverFieldNames, ...inputFieldNames])];
    mergedFields = ES.PrepareTemporalFields(mergedFields, mergedFieldNames, []);
    const options = ObjectCreate(null);
    options.overflow = 'reject';
    return ES.CalendarDateFromFields(calendar, mergedFields, options);
  }
  getISOFields(): Return['getISOFields'] {
    if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
    return {
      calendar: GetSlot(this, CALENDAR),
      isoDay: GetSlot(this, ISO_DAY),
      isoMonth: GetSlot(this, ISO_MONTH),
      isoYear: GetSlot(this, ISO_YEAR)
    };
  }
  static from(item: Params['from'][0], optionsParam: Params['from'][1] = undefined): Return['from'] {
    const options = ES.GetOptionsObject(optionsParam);
    if (ES.IsTemporalYearMonth(item)) {
      ES.ToTemporalOverflow(options); // validate and ignore
      return ES.CreateTemporalYearMonth(
        GetSlot(item, ISO_YEAR),
        GetSlot(item, ISO_MONTH),
        GetSlot(item, CALENDAR),
        GetSlot(item, ISO_DAY)
      );
    }
    return ES.ToTemporalYearMonth(item, options);
  }
  static compare(oneParam: Params['compare'][0], twoParam: Params['compare'][1]): Return['compare'] {
    const one = ES.ToTemporalYearMonth(oneParam);
    const two = ES.ToTemporalYearMonth(twoParam);
    return ES.CompareISODate(
      GetSlot(one, ISO_YEAR),
      GetSlot(one, ISO_MONTH),
      GetSlot(one, ISO_DAY),
      GetSlot(two, ISO_YEAR),
      GetSlot(two, ISO_MONTH),
      GetSlot(two, ISO_DAY)
    );
  }
  [Symbol.toStringTag]!: 'Temporal.PlainYearMonth';
}

MakeIntrinsicClass(PlainYearMonth, 'Temporal.PlainYearMonth');