diff --git a/crates/oxide_builtins/src/temporal/common.rs b/crates/oxide_builtins/src/temporal/common.rs
new file mode 100644
index 00000000..9bdafca4
--- /dev/null
+++ b/crates/oxide_builtins/src/temporal/common.rs
@@ -0,0 +1,551 @@
+//! Temporal 命名空间的最小实现子集：Temporal.Now / Temporal.Instant /
+//! Temporal.PlainDate / Temporal.PlainTime / Temporal.PlainDateTime /
+//! Temporal.PlainMonthDay / Temporal.PlainYearMonth / Temporal.ZonedDateTime。
+//! 内部数据按对象类型存入 prop 槽：
+//! Instant 存纪元纳秒（BigInt，prop 0）、PlainDate 存年/月/日/日历 ID（prop 0-3）、
+//! PlainTime 存午夜后纳秒（f64，prop 0）、PlainDateTime 存年/月/日/午夜后纳秒/日历 ID（prop 0-4）、
+//! PlainMonthDay 存月/日/参考年/日历 ID（prop 0-3）、
+//! PlainYearMonth 存年/月/参考日/日历 ID（prop 0-3）、
+//! ZonedDateTime 存纪元纳秒、时区 ID、日历 ID（prop 0-2）。
+//! 日历 ID 未显式给定时统一取 "iso8601"。
+
+use num_traits::ToPrimitive;
+use oxide_kernel::shape_forge::EMPTY_SHAPE_ID;
+use oxide_runtime_api::{to_number, to_string, NativeResult, VmHost};
+use oxide_types::object::JsObject;
+use oxide_types::value::JsValue;
+
+use super::{
+    days_in_month, parse_temporal_calendar_string, temporal_calendar_id, valid_iso_date, valid_plain_date_time_range,
+    valid_plain_time,
+};
+
+pub(crate) const MAX_INSTANT_NS: i128 = 8_640_000_000_000_000_000_000;
+
+macro_rules! native_try {
+    ($expr:expr) => {
+        match $expr {
+            Ok(value) => value,
+            Err(err) => return NativeResult::Err(err),
+        }
+    };
+}
+pub(crate) use native_try;
+
+pub(crate) fn get_double_prop(obj: &JsObject, pos: usize) -> f64 {
+    let v = obj.get_prop_at(pos);
+    if v.is_double() {
+        v.as_double()
+    } else {
+        f64::NAN
+    }
+}
+
+/// 读对象日历槽：字符串槽直接返回，undefined/非 string 兜底 `"iso8601"`。
+/// 只读 prop 槽，不触发属性 getter，getter 与日历传播共用。
+pub(crate) fn get_calendar_id(obj: &JsObject, slot: usize) -> String {
+    let value = obj.get_prop_at(slot);
+    if value.is_string() {
+        to_string(value)
+    } else {
+        "iso8601".to_string()
+    }
+}
+
+pub(crate) fn get_instant_epoch_ns(obj: &JsObject) -> Option<i128> {
+    let value = obj.get_prop_at(0);
+    if value.is_bigint() {
+        return Some(unsafe { oxide_runtime_api::bigint_data(value) }.to_i128().unwrap_or(i128::MAX));
+    }
+    if value.is_int() || value.is_double() {
+        return Some(to_number(value) as i128);
+    }
+    None
+}
+
+pub(crate) fn ensure_instant<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
+    if !obj.is_instant_obj() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(())
+}
+
+pub(crate) fn ensure_plain_date<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
+    if !obj.is_plain_date_obj() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(())
+}
+
+pub(crate) fn ensure_plain_time<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
+    if !obj.is_plain_time_obj() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(())
+}
+
+pub(crate) fn ensure_plain_date_time<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
+    if !obj.is_plain_date_time_obj() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(())
+}
+
+pub(crate) fn ensure_duration<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
+    if !obj.is_duration_obj() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(())
+}
+
+pub(crate) fn ensure_zoned_date_time<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
+    if !obj.is_zoned_date_time_obj() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(())
+}
+
+pub(crate) fn receiver_obj<H: VmHost>(vm: &mut H, args: &[u8]) -> Result<*mut JsObject, JsValue> {
+    let raw = vm.reg(if args.is_empty() { 0 } else { args[0] });
+    if !raw.is_object() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    let ptr = raw.as_js_object_ptr();
+    if ptr.is_null() {
+        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
+    }
+    Ok(ptr)
+}
+
+pub(crate) fn initialize_temporal_receiver<H: VmHost, const N: usize>(
+    vm: &mut H, args: &[u8], type_tag: u8, values: [JsValue; N],
+) -> NativeResult {
+    let ptr = native_try!(receiver_obj(vm, args));
+    let obj = unsafe { &mut *ptr };
+    obj.type_tag = type_tag;
+    for (index, value) in values.into_iter().enumerate() {
+        obj.set_prop_at(index, value);
+    }
+    NativeResult::Ok(JsValue::undefined())
+}
+
+/// 读 receiver 是否为构造调用：`new` 时 this 的原型链包含相应构造器的 prototype。
+pub(crate) fn is_ctor_call<H: VmHost>(vm: &mut H, args: &[u8], proto_ptr: *const JsObject) -> bool {
+    let this_val = vm.reg(if args.is_empty() { 0 } else { args[0] });
+    if !this_val.is_object() {
+        return false;
+    }
+    let ptr = this_val.as_js_object_ptr();
+    if ptr.is_null() {
+        return false;
+    }
+    let obj = unsafe { &*ptr };
+    let mut this_proto = obj.proto();
+    while this_proto.is_object() {
+        let this_proto_ptr = this_proto.as_js_object_ptr();
+        if this_proto_ptr.is_null() {
+            return false;
+        }
+        if std::ptr::eq(this_proto_ptr, proto_ptr) {
+            return true;
+        }
+        this_proto = unsafe { &*this_proto_ptr }.proto();
+    }
+    false
+}
+
+pub(crate) fn make_instant<H: VmHost>(vm: &mut H, epoch_ns: i128) -> NativeResult {
+    let proto = JsValue::from_js_object(vm.session().builtin_world().instant_proto.as_ptr() as *mut JsObject);
+    let epoch_value = vm.new_bigint(num_bigint::BigInt::from(epoch_ns));
+    let mut obj = JsObject::new_empty(EMPTY_SHAPE_ID, proto);
+    obj.type_tag = JsObject::OBJ_TYPE_INSTANT;
+    obj.set_prop_at(0, epoch_value);
+    NativeResult::Ok(JsValue::from_js_object(vm.alloc_object(obj)))
+}
+
+pub(crate) fn make_zoned_date_time<H: VmHost>(
+    vm: &mut H, epoch_ns: i128, time_zone_id: &str, calendar: &str,
+) -> NativeResult {
+    let proto = JsValue::from_js_object(vm.session().builtin_world().zoned_date_time_proto.as_ptr() as *mut JsObject);
+    let epoch_value = vm.new_bigint(num_bigint::BigInt::from(epoch_ns));
+    let time_zone_value = vm.new_string(time_zone_id);
+    let calendar_value = vm.new_string(calendar);
+    let mut obj = JsObject::new_empty(EMPTY_SHAPE_ID, proto);
+    obj.type_tag = JsObject::OBJ_TYPE_ZONED_DATE_TIME;
+    obj.set_prop_at(0, epoch_value);
+    obj.set_prop_at(1, time_zone_value);
+    obj.set_prop_at(2, calendar_value);
+    NativeResult::Ok(JsValue::from_js_object(vm.alloc_object(obj)))
+}
+
+pub(crate) fn native_engine_error<H: VmHost>(vm: &mut H, error: &str) -> JsValue {
+    vm.take_uncaught_value()
+        .unwrap_or_else(|| crate::error::create_from_text(vm, error))
+}
+
+pub(crate) fn temporal_option_value<H: VmHost>(
+    vm: &mut H, obj: &JsObject, receiver: JsValue, name: &str,
+) -> Result<JsValue, JsValue> {
+    let key = vm.new_string(name);
+    let si = vm.property_key_si(key);
+    vm.ordinary_get(obj, si, receiver)
+        .map_err(|error| native_engine_error(vm, &error))
+}
+
+pub(crate) fn temporal_option_number<H: VmHost>(vm: &mut H, value: JsValue) -> Result<f64, JsValue> {
+    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::Number, vm)
+        .map_err(|error| native_engine_error(vm, &error))?;
+    if primitive.is_symbol() || primitive.is_bigint() {
+        return Err(crate::error::create_type_error(vm, "cannot convert option to number"));
+    }
+    Ok(to_number(primitive))
+}
+
+pub(crate) fn temporal_option_string<H: VmHost>(vm: &mut H, value: JsValue) -> Result<String, JsValue> {
+    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::String, vm)
+        .map_err(|error| native_engine_error(vm, &error))?;
+    if primitive.is_symbol() {
+        return Err(crate::error::create_type_error(vm, "cannot convert option to string"));
+    }
+    Ok(to_string(primitive))
+}
+
+/// ToPrimitive(String) 后要求结果为字符串，否则 TypeError（ParseMonthCode/ToOffsetString 语义）。
+pub(crate) fn temporal_string_strict<H: VmHost>(vm: &mut H, value: JsValue) -> Result<String, JsValue> {
+    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::String, vm)
+        .map_err(|error| native_engine_error(vm, &error))?;
+    if !primitive.is_string() {
+        return Err(crate::error::create_type_error(vm, "expected a string"));
+    }
+    Ok(to_string(primitive))
+}
+
+/// RejectObjectWithCalendarOrTimeZone：非对象 / Temporal 实例 / calendar、timeZone 非 undefined
+/// 均返回 TypeError（with 的 partial 参数校验）。
+///
+/// # 边界与前提
+/// - Temporal 内部槽检查先于 calendar/timeZone 的 Get（IsPartialTemporalObject 步骤序）。
+/// - 参数校验通过后调用方才能读字段。
+pub(crate) fn reject_partial_object_with_calendar_or_time_zone<H: VmHost>(
+    vm: &mut H, value: JsValue,
+) -> Result<(), JsValue> {
+    if !value.is_object() {
+        return Err(crate::error::create_type_error(vm, "invalid argument"));
+    }
+    let ptr = value.as_js_object_ptr();
+    if ptr.is_null() {
+        return Err(crate::error::create_type_error(vm, "invalid argument"));
+    }
+    let obj = unsafe { &*ptr };
+    if obj.is_plain_date_obj()
+        || obj.is_plain_date_time_obj()
+        || obj.is_plain_time_obj()
+        || obj.is_zoned_date_time_obj()
+        || obj.is_plain_month_day_obj()
+        || obj.is_plain_year_month_obj()
+    {
+        return Err(crate::error::create_type_error(vm, "invalid argument"));
+    }
+    let calendar = temporal_option_value(vm, obj, value, "calendar")?;
+    if !calendar.is_undefined() {
+        return Err(crate::error::create_type_error(vm, "invalid argument"));
+    }
+    let time_zone = temporal_option_value(vm, obj, value, "timeZone")?;
+    if !time_zone.is_undefined() {
+        return Err(crate::error::create_type_error(vm, "invalid argument"));
+    }
+    Ok(())
+}
+
+pub(crate) fn plain_date_time_object_parts<H: VmHost>(
+    vm: &mut H, value: JsValue, obj: &JsObject, constrain: bool, ignore_time: bool,
+) -> Result<(i32, u32, u32, f64, Option<String>), JsValue> {
+    let calendar_raw = temporal_option_value(vm, obj, value, "calendar")?;
+    let calendar = temporal_calendar_id(vm, calendar_raw)?;
+
+    // 先按规范顺序读取全部原始字段，暂不转换类型；PlainDate 路径忽略时间字段。
+    let (
+        day_raw,
+        hour_raw,
+        microsecond_raw,
+        millisecond_raw,
+        minute_raw,
+        month_raw,
+        month_code_raw,
+        nanosecond_raw,
+        second_raw,
+        year_raw,
+    ) = if ignore_time {
+        (
+            temporal_option_value(vm, obj, value, "day")?,
+            JsValue::undefined(),
+            JsValue::undefined(),
+            JsValue::undefined(),
+            JsValue::undefined(),
+            temporal_option_value(vm, obj, value, "month")?,
+            temporal_option_value(vm, obj, value, "monthCode")?,
+            JsValue::undefined(),
+            JsValue::undefined(),
+            temporal_option_value(vm, obj, value, "year")?,
+        )
+    } else {
+        (
+            temporal_option_value(vm, obj, value, "day")?,
+            temporal_option_value(vm, obj, value, "hour")?,
+            temporal_option_value(vm, obj, value, "microsecond")?,
+            temporal_option_value(vm, obj, value, "millisecond")?,
+            temporal_option_value(vm, obj, value, "minute")?,
+            temporal_option_value(vm, obj, value, "month")?,
+            temporal_option_value(vm, obj, value, "monthCode")?,
+            temporal_option_value(vm, obj, value, "nanosecond")?,
+            temporal_option_value(vm, obj, value, "second")?,
+            temporal_option_value(vm, obj, value, "year")?,
+        )
+    };
+
+    // 缺失必填字段先抛 TypeError（先于任何 RangeError 值校验）。
+    if day_raw.is_undefined() {
+        return Err(crate::error::create_type_error(vm, "day is required"));
+    }
+    if year_raw.is_undefined() {
+        return Err(crate::error::create_type_error(vm, "year is required"));
+    }
+    if month_raw.is_undefined() && month_code_raw.is_undefined() {
+        return Err(crate::error::create_type_error(vm, "month is required"));
+    }
+
+    // monthCode 必须是 string 类型，否则 TypeError。
+    let month_code = if month_code_raw.is_undefined() {
+        None
+    } else {
+        if !month_code_raw.is_string() {
+            return Err(crate::error::create_type_error(vm, "monthCode must be a string"));
+        }
+        let code = to_string(month_code_raw);
+        // 语法（well-formed）：M 后两位数字，可选 L 后缀。
+        let digits_ok =
+            code.len() >= 3 && code.starts_with('M') && code.as_bytes()[1..3].iter().all(u8::is_ascii_digit);
+        let well_formed = digits_ok && (code.len() == 3 || (code.len() == 4 && code.ends_with('L')));
+        if !well_formed {
+            return Err(crate::error::create_range_error(vm, "invalid monthCode"));
+        }
+        Some((code.clone(), code.ends_with('L')))
+    };
+
+    // 数值字段类型转换：Symbol/BigInt 抛 TypeError。
+    let mut convert_number = |_name: &str, raw: JsValue| -> Result<Option<f64>, JsValue> {
+        if raw.is_undefined() {
+            Ok(None)
+        } else {
+            temporal_option_number(vm, raw).map(|number| Some(number.trunc()))
+        }
+    };
+    let (day, hour, microsecond, millisecond, minute, month, nanosecond, second, year) = (
+        convert_number("day", day_raw)?,
+        convert_number("hour", hour_raw)?.unwrap_or(0.0),
+        convert_number("microsecond", microsecond_raw)?.unwrap_or(0.0),
+        convert_number("millisecond", millisecond_raw)?.unwrap_or(0.0),
+        convert_number("minute", minute_raw)?.unwrap_or(0.0),
+        convert_number("month", month_raw)?,
+        convert_number("nanosecond", nanosecond_raw)?.unwrap_or(0.0),
+        convert_number("second", second_raw)?.unwrap_or(0.0),
+        convert_number("year", year_raw)?,
+    );
+
+    // monthCode 适配 ISO 日历：仅 M01-M12，L 后缀不支持；无效抛 RangeError。
+    let month_code = match month_code {
+        Some((code, leap)) => {
+            if leap {
+                return Err(crate::error::create_range_error(vm, "monthCode is not valid for ISO calendar"));
+            }
+            let number = code[1..3]
+                .parse::<f64>()
+                .map_err(|_| crate::error::create_range_error(vm, "invalid monthCode"))?;
+            if !(1.0..=12.0).contains(&number) {
+                return Err(crate::error::create_range_error(vm, "monthCode is not valid for ISO calendar"));
+            }
+            Some(number)
+        }
+        None => None,
+    };
+    let month = match (month, month_code) {
+        (Some(month), Some(code)) if month != code => {
+            return Err(crate::error::create_range_error(vm, "month and monthCode disagree"));
+        }
+        (Some(month), _) => month,
+        (None, Some(code)) => code,
+        (None, None) => unreachable!(),
+    };
+    let day = day.ok_or_else(|| crate::error::create_type_error(vm, "day is required"))?;
+    let year = year.ok_or_else(|| crate::error::create_type_error(vm, "year is required"))?;
+    let mut values = [year, month, day, hour, minute, second, millisecond, microsecond, nanosecond];
+    if values.iter().any(|number| !number.is_finite()) || values[1..].iter().any(|number| *number < 0.0) {
+        return Err(crate::error::create_range_error(vm, "invalid date-time component"));
+    }
+    if constrain {
+        if values[1] < 1.0 || values[2] < 1.0 {
+            return Err(crate::error::create_range_error(vm, "invalid date-time component"));
+        }
+        values[1] = values[1].clamp(1.0, 12.0);
+        values[2] = values[2].clamp(1.0, days_in_month(values[0] as i128, values[1] as i128).unwrap_or(31) as f64);
+        values[3] = values[3].clamp(0.0, 23.0);
+        values[4] = values[4].clamp(0.0, 59.0);
+        values[5] = values[5].clamp(0.0, 59.0);
+        values[6] = values[6].clamp(0.0, 999.0);
+        values[7] = values[7].clamp(0.0, 999.0);
+        values[8] = values[8].clamp(0.0, 999.0);
+    }
+    let [year, month, day, hour, minute, second, millisecond, microsecond, nanosecond] = values;
+    let (year, month, day) = (year as i32, month as u32, day as u32);
+    let (hour, minute, second) = (hour as u32, minute as u32, second as u32);
+    let (millisecond, microsecond, nanosecond) = (millisecond as u32, microsecond as u32, nanosecond as u32);
+    if !valid_iso_date(year, month, day)
+        || (!ignore_time && !valid_plain_time(hour, minute, second, millisecond, microsecond, nanosecond))
+    {
+        return Err(crate::error::create_range_error(vm, "invalid date-time component"));
+    }
+    let total_ns = hour as f64 * 3_600_000_000_000.0
+        + minute as f64 * 60_000_000_000.0
+        + second as f64 * 1_000_000_000.0
+        + millisecond as f64 * 1_000_000.0
+        + microsecond as f64 * 1_000.0
+        + nanosecond as f64;
+    if !ignore_time && !valid_plain_date_time_range(year, month, day, total_ns) {
+        return Err(crate::error::create_range_error(vm, "invalid date-time component"));
+    }
+    Ok((year, month, day, total_ns, calendar))
+}
+
+pub(crate) fn temporal_overflow<H: VmHost>(vm: &mut H, args: &[u8]) -> Result<bool, JsValue> {
+    let options = if args.len() > 2 { vm.reg(args[2]) } else { JsValue::undefined() };
+    if options.is_undefined() {
+        return Ok(true);
+    }
+    if !options.is_object() {
+        return Err(crate::error::create_type_error(vm, "options must be an object"));
+    }
+    let ptr = options.as_js_object_ptr();
+    if ptr.is_null() {
+        return Err(crate::error::create_type_error(vm, "options must be an object"));
+    }
+    let raw = temporal_option_value(vm, unsafe { &*ptr }, options, "overflow")?;
+    if raw.is_undefined() {
+        return Ok(true);
+    }
+    let value = temporal_option_string(vm, raw)?;
+    match value.as_str() {
+        "constrain" => Ok(true),
+        "reject" => Ok(false),
+        _ => Err(crate::error::create_range_error(vm, "invalid overflow")),
+    }
+}
+
+/// Temporal 数字分量转换（number-only 路径）：先 ToPrimitive(Number)——对象经
+/// valueOf/toString 取值；Symbol/BigInt → TypeError；NaN/±Inf → RangeError
+/// （undefined 与不可解析串都归 NaN，由此统一抛 RangeError）；其余截断取整。
+pub(crate) fn temporal_number_component<H: VmHost>(vm: &mut H, value: JsValue) -> Result<f64, JsValue> {
+    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::Number, vm)
+        .map_err(|error| native_engine_error(vm, &error))?;
+    if primitive.is_symbol() || primitive.is_bigint() {
+        return Err(crate::error::create_type_error(vm, "invalid number"));
+    }
+    let number = to_number(primitive);
+    if number.is_infinite() || number.is_nan() {
+        return Err(crate::error::create_range_error(vm, "invalid number"));
+    }
+    Ok(number.trunc())
+}
+
+/// ISO 年-月是否落在 PlainYearMonth 可表示范围（ISOYearMonthWithinLimits）：
+/// 年超 ±271821..=275760、或 -271821 年 3 月及以前、+275760 年 10 月及以后越界。
+pub(crate) fn iso_year_month_within_limits(year: i32, month: u32) -> bool {
+    if !(-271_821..=275_760).contains(&year) {
+        return false;
+    }
+    !((year == -271_821 && month < 4) || (year == 275_760 && month > 9))
+}
+
+/// toString 的 calendarName 选项取值（缺省 = auto；auto 与 never 的差异仅在注解）。
+pub(crate) enum ShowCalendar {
+    Auto,
+    Always,
+    Critical,
+    Never,
+}
+
+/// ISO 串尾部日历注解（FormatCalendarAnnotation）：never 与 auto+iso8601 为空；
+/// critical 前置 `!`；其余为 `[u-ca=…]`。
+pub(crate) fn calendar_annotation(calendar: &str, show: ShowCalendar) -> String {
+    match (show, calendar) {
+        (ShowCalendar::Never, _) => String::new(),
+        (ShowCalendar::Auto, "iso8601") => String::new(),
+        (ShowCalendar::Always, _) => format!("[u-ca={calendar}]"),
+        (ShowCalendar::Critical, _) => format!("[!u-ca={calendar}]"),
+        (ShowCalendar::Auto, _) => format!("[u-ca={calendar}]"),
+    }
+}
+
+/// 读并校验 toString 的 calendarName 选项：options 非对象 → TypeError；
+/// 值非字符串先 ToPrimitive(String) 转换（Symbol → TypeError）；
+/// 仅 auto/always/never/critical 合法（大小写敏感），否则 RangeError。
+pub(crate) fn temporal_to_show_calendar<H: VmHost>(vm: &mut H, args: &[u8]) -> Result<ShowCalendar, JsValue> {
+    let options = if args.len() > 1 { vm.reg(args[1]) } else { JsValue::undefined() };
+    if options.is_undefined() {
+        return Ok(ShowCalendar::Auto);
+    }
+    if !options.is_object() {
+        return Err(crate::error::create_type_error(vm, "options must be an object"));
+    }
+    let ptr = options.as_js_object_ptr();
+    if ptr.is_null() {
+        return Err(crate::error::create_type_error(vm, "options must be an object"));
+    }
+    let raw = temporal_option_value(vm, unsafe { &*ptr }, options, "calendarName")?;
+    if raw.is_undefined() {
+        return Ok(ShowCalendar::Auto);
+    }
+    let value = temporal_option_string(vm, raw)?;
+    match value.as_str() {
+        "always" => Ok(ShowCalendar::Always),
+        "critical" => Ok(ShowCalendar::Critical),
+        "never" => Ok(ShowCalendar::Never),
+        "auto" => Ok(ShowCalendar::Auto),
+        _ => Err(crate::error::create_range_error(vm, "invalid calendarName")),
+    }
+}
+
+/// bag 日历解析：undefined → iso8601；字符串走宽松日历串解析（18-ID 白名单归一小写，
+/// 合法 ISO 日期-时间串归一 iso8601，含 YYYY-MM / MM-DD 部分日期）；
+/// PD/PDT/ZDT/PMD/PYM 实例 → 直读日历槽；其余对象与原始值 → TypeError。
+pub(crate) fn month_day_bag_calendar_id<H: VmHost>(vm: &mut H, value: JsValue) -> Result<String, JsValue> {
+    if value.is_undefined() {
+        return Ok("iso8601".to_string());
+    }
+    if value.is_string() {
+        let text = to_string(value);
+        return parse_temporal_calendar_string(&text)
+            .map_err(|_| crate::error::create_range_error(vm, "invalid calendar"));
+    }
+    if value.is_object() {
+        let ptr = value.as_js_object_ptr();
+        if !ptr.is_null() {
+            let obj = unsafe { &*ptr };
+            let slot = if obj.is_plain_date_obj() {
+                Some(3)
+            } else if obj.is_plain_date_time_obj() {
+                Some(4)
+            } else if obj.is_zoned_date_time_obj() {
+                Some(2)
+            } else if obj.is_plain_month_day_obj() || obj.is_plain_year_month_obj() {
+                Some(3)
+            } else {
+                None
+            };
+            if let Some(slot) = slot {
+                return Ok(get_calendar_id(obj, slot));
+            }
+        }
+        return Err(crate::error::create_type_error(vm, "invalid calendar"));
+    }
+    Err(crate::error::create_type_error(vm, "invalid calendar"))
+}
diff --git a/crates/oxide_builtins/src/temporal/mod.rs b/crates/oxide_builtins/src/temporal/mod.rs
index 926e92a0..2dc766f7 100644
--- a/crates/oxide_builtins/src/temporal/mod.rs
+++ b/crates/oxide_builtins/src/temporal/mod.rs
@@ -6,171 +6,9 @@ use oxide_runtime_api::{to_number, to_string, NativeResult, VmHost};
 use oxide_types::object::JsObject;
 use oxide_types::value::JsValue;
 
-// Temporal 命名空间的最小实现子集：Temporal.Now / Temporal.Instant /
-// Temporal.PlainDate / Temporal.PlainTime / Temporal.PlainDateTime /
-// Temporal.PlainMonthDay / Temporal.PlainYearMonth / Temporal.ZonedDateTime。
-// 内部数据按对象类型存入 prop 槽：
-// Instant 存纪元纳秒（BigInt，prop 0）、PlainDate 存年/月/日/日历 ID（prop 0-3）、
-// PlainTime 存午夜后纳秒（f64，prop 0）、PlainDateTime 存年/月/日/午夜后纳秒/日历 ID（prop 0-4）、
-// PlainMonthDay 存月/日/参考年/日历 ID（prop 0-3）、
-// PlainYearMonth 存年/月/参考日/日历 ID（prop 0-3）、
-// ZonedDateTime 存纪元纳秒、时区 ID、日历 ID（prop 0-2）。
-// 日历 ID 未显式给定时统一取 "iso8601"。
+mod common;
 
-const MAX_INSTANT_NS: i128 = 8_640_000_000_000_000_000_000;
-
-macro_rules! native_try {
-    ($expr:expr) => {
-        match $expr {
-            Ok(value) => value,
-            Err(err) => return NativeResult::Err(err),
-        }
-    };
-}
-
-fn get_double_prop(obj: &JsObject, pos: usize) -> f64 {
-    let v = obj.get_prop_at(pos);
-    if v.is_double() {
-        v.as_double()
-    } else {
-        f64::NAN
-    }
-}
-
-/// 读对象日历槽：字符串槽直接返回，undefined/非 string 兜底 `"iso8601"`。
-/// 只读 prop 槽，不触发属性 getter，getter 与日历传播共用。
-fn get_calendar_id(obj: &JsObject, slot: usize) -> String {
-    let value = obj.get_prop_at(slot);
-    if value.is_string() {
-        to_string(value)
-    } else {
-        "iso8601".to_string()
-    }
-}
-
-fn get_instant_epoch_ns(obj: &JsObject) -> Option<i128> {
-    let value = obj.get_prop_at(0);
-    if value.is_bigint() {
-        return Some(unsafe { oxide_runtime_api::bigint_data(value) }.to_i128().unwrap_or(i128::MAX));
-    }
-    if value.is_int() || value.is_double() {
-        return Some(to_number(value) as i128);
-    }
-    None
-}
-
-fn ensure_instant<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
-    if !obj.is_instant_obj() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(())
-}
-
-fn ensure_plain_date<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
-    if !obj.is_plain_date_obj() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(())
-}
-
-fn ensure_plain_time<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
-    if !obj.is_plain_time_obj() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(())
-}
-
-fn ensure_plain_date_time<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
-    if !obj.is_plain_date_time_obj() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(())
-}
-
-fn ensure_duration<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
-    if !obj.is_duration_obj() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(())
-}
-
-fn ensure_zoned_date_time<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(), JsValue> {
-    if !obj.is_zoned_date_time_obj() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(())
-}
-
-fn receiver_obj<H: VmHost>(vm: &mut H, args: &[u8]) -> Result<*mut JsObject, JsValue> {
-    let raw = vm.reg(if args.is_empty() { 0 } else { args[0] });
-    if !raw.is_object() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    let ptr = raw.as_js_object_ptr();
-    if ptr.is_null() {
-        return Err(crate::error::create_type_error(vm, "called on incompatible receiver"));
-    }
-    Ok(ptr)
-}
-
-fn initialize_temporal_receiver<H: VmHost, const N: usize>(
-    vm: &mut H, args: &[u8], type_tag: u8, values: [JsValue; N],
-) -> NativeResult {
-    let ptr = native_try!(receiver_obj(vm, args));
-    let obj = unsafe { &mut *ptr };
-    obj.type_tag = type_tag;
-    for (index, value) in values.into_iter().enumerate() {
-        obj.set_prop_at(index, value);
-    }
-    NativeResult::Ok(JsValue::undefined())
-}
-
-/// 读 receiver 是否为构造调用：`new` 时 this 的原型链包含相应构造器的 prototype。
-fn is_ctor_call<H: VmHost>(vm: &mut H, args: &[u8], proto_ptr: *const JsObject) -> bool {
-    let this_val = vm.reg(if args.is_empty() { 0 } else { args[0] });
-    if !this_val.is_object() {
-        return false;
-    }
-    let ptr = this_val.as_js_object_ptr();
-    if ptr.is_null() {
-        return false;
-    }
-    let obj = unsafe { &*ptr };
-    let mut this_proto = obj.proto();
-    while this_proto.is_object() {
-        let this_proto_ptr = this_proto.as_js_object_ptr();
-        if this_proto_ptr.is_null() {
-            return false;
-        }
-        if std::ptr::eq(this_proto_ptr, proto_ptr) {
-            return true;
-        }
-        this_proto = unsafe { &*this_proto_ptr }.proto();
-    }
-    false
-}
-
-fn make_instant<H: VmHost>(vm: &mut H, epoch_ns: i128) -> NativeResult {
-    let proto = JsValue::from_js_object(vm.session().builtin_world().instant_proto.as_ptr() as *mut JsObject);
-    let epoch_value = vm.new_bigint(num_bigint::BigInt::from(epoch_ns));
-    let mut obj = JsObject::new_empty(EMPTY_SHAPE_ID, proto);
-    obj.type_tag = JsObject::OBJ_TYPE_INSTANT;
-    obj.set_prop_at(0, epoch_value);
-    NativeResult::Ok(JsValue::from_js_object(vm.alloc_object(obj)))
-}
-
-fn make_zoned_date_time<H: VmHost>(vm: &mut H, epoch_ns: i128, time_zone_id: &str, calendar: &str) -> NativeResult {
-    let proto = JsValue::from_js_object(vm.session().builtin_world().zoned_date_time_proto.as_ptr() as *mut JsObject);
-    let epoch_value = vm.new_bigint(num_bigint::BigInt::from(epoch_ns));
-    let time_zone_value = vm.new_string(time_zone_id);
-    let calendar_value = vm.new_string(calendar);
-    let mut obj = JsObject::new_empty(EMPTY_SHAPE_ID, proto);
-    obj.type_tag = JsObject::OBJ_TYPE_ZONED_DATE_TIME;
-    obj.set_prop_at(0, epoch_value);
-    obj.set_prop_at(1, time_zone_value);
-    obj.set_prop_at(2, calendar_value);
-    NativeResult::Ok(JsValue::from_js_object(vm.alloc_object(obj)))
-}
+use common::*;
 
 fn parse_digits(bytes: &[u8], cursor: &mut usize, count: usize) -> Option<i128> {
     let end = cursor.checked_add(count)?;
@@ -428,11 +266,6 @@ fn parse_instant_string(s: &str) -> Option<i128> {
     (epoch_ns.unsigned_abs() <= MAX_INSTANT_NS as u128).then_some(epoch_ns)
 }
 
-fn native_engine_error<H: VmHost>(vm: &mut H, error: &str) -> JsValue {
-    vm.take_uncaught_value()
-        .unwrap_or_else(|| crate::error::create_from_text(vm, error))
-}
-
 fn primitive_to_bigint<H: VmHost>(vm: &mut H, raw: JsValue) -> Result<i128, JsValue> {
     let primitive = oxide_runtime_api::to_primitive(raw, oxide_runtime_api::ToPrimitiveHint::Number, vm)
         .map_err(|error| native_engine_error(vm, &error))?;
@@ -676,33 +509,6 @@ enum InstantRoundingMode {
     Trunc,
 }
 
-fn temporal_option_value<H: VmHost>(
-    vm: &mut H, obj: &JsObject, receiver: JsValue, name: &str,
-) -> Result<JsValue, JsValue> {
-    let key = vm.new_string(name);
-    let si = vm.property_key_si(key);
-    vm.ordinary_get(obj, si, receiver)
-        .map_err(|error| native_engine_error(vm, &error))
-}
-
-fn temporal_option_number<H: VmHost>(vm: &mut H, value: JsValue) -> Result<f64, JsValue> {
-    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::Number, vm)
-        .map_err(|error| native_engine_error(vm, &error))?;
-    if primitive.is_symbol() || primitive.is_bigint() {
-        return Err(crate::error::create_type_error(vm, "cannot convert option to number"));
-    }
-    Ok(to_number(primitive))
-}
-
-fn temporal_option_string<H: VmHost>(vm: &mut H, value: JsValue) -> Result<String, JsValue> {
-    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::String, vm)
-        .map_err(|error| native_engine_error(vm, &error))?;
-    if primitive.is_symbol() {
-        return Err(crate::error::create_type_error(vm, "cannot convert option to string"));
-    }
-    Ok(to_string(primitive))
-}
-
 fn instant_rounding_mode(value: &str) -> Option<InstantRoundingMode> {
     match value {
         "ceil" => Some(InstantRoundingMode::Ceil),
@@ -2063,51 +1869,6 @@ struct ZdtMergedFields {
     bag_offset: Option<i32>,
 }
 
-/// ToPrimitive(String) 后要求结果为字符串，否则 TypeError（ParseMonthCode/ToOffsetString 语义）。
-fn temporal_string_strict<H: VmHost>(vm: &mut H, value: JsValue) -> Result<String, JsValue> {
-    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::String, vm)
-        .map_err(|error| native_engine_error(vm, &error))?;
-    if !primitive.is_string() {
-        return Err(crate::error::create_type_error(vm, "expected a string"));
-    }
-    Ok(to_string(primitive))
-}
-
-/// RejectObjectWithCalendarOrTimeZone：非对象 / Temporal 实例 / calendar、timeZone 非 undefined
-/// 均返回 TypeError（with 的 partial 参数校验）。
-///
-/// # 边界与前提
-/// - Temporal 内部槽检查先于 calendar/timeZone 的 Get（IsPartialTemporalObject 步骤序）。
-/// - 参数校验通过后调用方才能读字段。
-fn reject_partial_object_with_calendar_or_time_zone<H: VmHost>(vm: &mut H, value: JsValue) -> Result<(), JsValue> {
-    if !value.is_object() {
-        return Err(crate::error::create_type_error(vm, "invalid argument"));
-    }
-    let ptr = value.as_js_object_ptr();
-    if ptr.is_null() {
-        return Err(crate::error::create_type_error(vm, "invalid argument"));
-    }
-    let obj = unsafe { &*ptr };
-    if obj.is_plain_date_obj()
-        || obj.is_plain_date_time_obj()
-        || obj.is_plain_time_obj()
-        || obj.is_zoned_date_time_obj()
-        || obj.is_plain_month_day_obj()
-        || obj.is_plain_year_month_obj()
-    {
-        return Err(crate::error::create_type_error(vm, "invalid argument"));
-    }
-    let calendar = temporal_option_value(vm, obj, value, "calendar")?;
-    if !calendar.is_undefined() {
-        return Err(crate::error::create_type_error(vm, "invalid argument"));
-    }
-    let time_zone = temporal_option_value(vm, obj, value, "timeZone")?;
-    if !time_zone.is_undefined() {
-        return Err(crate::error::create_type_error(vm, "invalid argument"));
-    }
-    Ok(())
-}
-
 /// with 的部分字段读取与合并：按字典序读 bag 字段，与 receiver 默认分量合并。
 ///
 /// # 步骤
@@ -5706,165 +5467,6 @@ fn temporal_calendar_id_strict<H: VmHost>(vm: &mut H, value: JsValue) -> Result<
     temporal_calendar_id(vm, value)
 }
 
-fn plain_date_time_object_parts<H: VmHost>(
-    vm: &mut H, value: JsValue, obj: &JsObject, constrain: bool, ignore_time: bool,
-) -> Result<(i32, u32, u32, f64, Option<String>), JsValue> {
-    let calendar_raw = temporal_option_value(vm, obj, value, "calendar")?;
-    let calendar = temporal_calendar_id(vm, calendar_raw)?;
-
-    // 先按规范顺序读取全部原始字段，暂不转换类型；PlainDate 路径忽略时间字段。
-    let (
-        day_raw,
-        hour_raw,
-        microsecond_raw,
-        millisecond_raw,
-        minute_raw,
-        month_raw,
-        month_code_raw,
-        nanosecond_raw,
-        second_raw,
-        year_raw,
-    ) = if ignore_time {
-        (
-            temporal_option_value(vm, obj, value, "day")?,
-            JsValue::undefined(),
-            JsValue::undefined(),
-            JsValue::undefined(),
-            JsValue::undefined(),
-            temporal_option_value(vm, obj, value, "month")?,
-            temporal_option_value(vm, obj, value, "monthCode")?,
-            JsValue::undefined(),
-            JsValue::undefined(),
-            temporal_option_value(vm, obj, value, "year")?,
-        )
-    } else {
-        (
-            temporal_option_value(vm, obj, value, "day")?,
-            temporal_option_value(vm, obj, value, "hour")?,
-            temporal_option_value(vm, obj, value, "microsecond")?,
-            temporal_option_value(vm, obj, value, "millisecond")?,
-            temporal_option_value(vm, obj, value, "minute")?,
-            temporal_option_value(vm, obj, value, "month")?,
-            temporal_option_value(vm, obj, value, "monthCode")?,
-            temporal_option_value(vm, obj, value, "nanosecond")?,
-            temporal_option_value(vm, obj, value, "second")?,
-            temporal_option_value(vm, obj, value, "year")?,
-        )
-    };
-
-    // 缺失必填字段先抛 TypeError（先于任何 RangeError 值校验）。
-    if day_raw.is_undefined() {
-        return Err(crate::error::create_type_error(vm, "day is required"));
-    }
-    if year_raw.is_undefined() {
-        return Err(crate::error::create_type_error(vm, "year is required"));
-    }
-    if month_raw.is_undefined() && month_code_raw.is_undefined() {
-        return Err(crate::error::create_type_error(vm, "month is required"));
-    }
-
-    // monthCode 必须是 string 类型，否则 TypeError。
-    let month_code = if month_code_raw.is_undefined() {
-        None
-    } else {
-        if !month_code_raw.is_string() {
-            return Err(crate::error::create_type_error(vm, "monthCode must be a string"));
-        }
-        let code = to_string(month_code_raw);
-        // 语法（well-formed）：M 后两位数字，可选 L 后缀。
-        let digits_ok =
-            code.len() >= 3 && code.starts_with('M') && code.as_bytes()[1..3].iter().all(u8::is_ascii_digit);
-        let well_formed = digits_ok && (code.len() == 3 || (code.len() == 4 && code.ends_with('L')));
-        if !well_formed {
-            return Err(crate::error::create_range_error(vm, "invalid monthCode"));
-        }
-        Some((code.clone(), code.ends_with('L')))
-    };
-
-    // 数值字段类型转换：Symbol/BigInt 抛 TypeError。
-    let mut convert_number = |_name: &str, raw: JsValue| -> Result<Option<f64>, JsValue> {
-        if raw.is_undefined() {
-            Ok(None)
-        } else {
-            temporal_option_number(vm, raw).map(|number| Some(number.trunc()))
-        }
-    };
-    let (day, hour, microsecond, millisecond, minute, month, nanosecond, second, year) = (
-        convert_number("day", day_raw)?,
-        convert_number("hour", hour_raw)?.unwrap_or(0.0),
-        convert_number("microsecond", microsecond_raw)?.unwrap_or(0.0),
-        convert_number("millisecond", millisecond_raw)?.unwrap_or(0.0),
-        convert_number("minute", minute_raw)?.unwrap_or(0.0),
-        convert_number("month", month_raw)?,
-        convert_number("nanosecond", nanosecond_raw)?.unwrap_or(0.0),
-        convert_number("second", second_raw)?.unwrap_or(0.0),
-        convert_number("year", year_raw)?,
-    );
-
-    // monthCode 适配 ISO 日历：仅 M01-M12，L 后缀不支持；无效抛 RangeError。
-    let month_code = match month_code {
-        Some((code, leap)) => {
-            if leap {
-                return Err(crate::error::create_range_error(vm, "monthCode is not valid for ISO calendar"));
-            }
-            let number = code[1..3]
-                .parse::<f64>()
-                .map_err(|_| crate::error::create_range_error(vm, "invalid monthCode"))?;
-            if !(1.0..=12.0).contains(&number) {
-                return Err(crate::error::create_range_error(vm, "monthCode is not valid for ISO calendar"));
-            }
-            Some(number)
-        }
-        None => None,
-    };
-    let month = match (month, month_code) {
-        (Some(month), Some(code)) if month != code => {
-            return Err(crate::error::create_range_error(vm, "month and monthCode disagree"));
-        }
-        (Some(month), _) => month,
-        (None, Some(code)) => code,
-        (None, None) => unreachable!(),
-    };
-    let day = day.ok_or_else(|| crate::error::create_type_error(vm, "day is required"))?;
-    let year = year.ok_or_else(|| crate::error::create_type_error(vm, "year is required"))?;
-    let mut values = [year, month, day, hour, minute, second, millisecond, microsecond, nanosecond];
-    if values.iter().any(|number| !number.is_finite()) || values[1..].iter().any(|number| *number < 0.0) {
-        return Err(crate::error::create_range_error(vm, "invalid date-time component"));
-    }
-    if constrain {
-        if values[1] < 1.0 || values[2] < 1.0 {
-            return Err(crate::error::create_range_error(vm, "invalid date-time component"));
-        }
-        values[1] = values[1].clamp(1.0, 12.0);
-        values[2] = values[2].clamp(1.0, days_in_month(values[0] as i128, values[1] as i128).unwrap_or(31) as f64);
-        values[3] = values[3].clamp(0.0, 23.0);
-        values[4] = values[4].clamp(0.0, 59.0);
-        values[5] = values[5].clamp(0.0, 59.0);
-        values[6] = values[6].clamp(0.0, 999.0);
-        values[7] = values[7].clamp(0.0, 999.0);
-        values[8] = values[8].clamp(0.0, 999.0);
-    }
-    let [year, month, day, hour, minute, second, millisecond, microsecond, nanosecond] = values;
-    let (year, month, day) = (year as i32, month as u32, day as u32);
-    let (hour, minute, second) = (hour as u32, minute as u32, second as u32);
-    let (millisecond, microsecond, nanosecond) = (millisecond as u32, microsecond as u32, nanosecond as u32);
-    if !valid_iso_date(year, month, day)
-        || (!ignore_time && !valid_plain_time(hour, minute, second, millisecond, microsecond, nanosecond))
-    {
-        return Err(crate::error::create_range_error(vm, "invalid date-time component"));
-    }
-    let total_ns = hour as f64 * 3_600_000_000_000.0
-        + minute as f64 * 60_000_000_000.0
-        + second as f64 * 1_000_000_000.0
-        + millisecond as f64 * 1_000_000.0
-        + microsecond as f64 * 1_000.0
-        + nanosecond as f64;
-    if !ignore_time && !valid_plain_date_time_range(year, month, day, total_ns) {
-        return Err(crate::error::create_range_error(vm, "invalid date-time component"));
-    }
-    Ok((year, month, day, total_ns, calendar))
-}
-
 /// 将 ZonedDateTime 按时区偏移转换为本地 PlainDateTime 分量。
 fn zoned_date_time_plain_parts<H: VmHost>(vm: &mut H, obj: &JsObject) -> Result<(i32, u32, u32, f64), JsValue> {
     let Some(epoch_ns) = get_instant_epoch_ns(obj) else {
@@ -5951,30 +5553,6 @@ fn plain_date_time_like_parts<H: VmHost>(
     plain_date_time_object_parts(vm, value, obj, constrain, false)
 }
 
-fn temporal_overflow<H: VmHost>(vm: &mut H, args: &[u8]) -> Result<bool, JsValue> {
-    let options = if args.len() > 2 { vm.reg(args[2]) } else { JsValue::undefined() };
-    if options.is_undefined() {
-        return Ok(true);
-    }
-    if !options.is_object() {
-        return Err(crate::error::create_type_error(vm, "options must be an object"));
-    }
-    let ptr = options.as_js_object_ptr();
-    if ptr.is_null() {
-        return Err(crate::error::create_type_error(vm, "options must be an object"));
-    }
-    let raw = temporal_option_value(vm, unsafe { &*ptr }, options, "overflow")?;
-    if raw.is_undefined() {
-        return Ok(true);
-    }
-    let value = temporal_option_string(vm, raw)?;
-    match value.as_str() {
-        "constrain" => Ok(true),
-        "reject" => Ok(false),
-        _ => Err(crate::error::create_range_error(vm, "invalid overflow")),
-    }
-}
-
 /// `Temporal.PlainDateTime.from(item)`：从实例、ISO 字符串或字段对象创建副本。
 pub fn plain_date_time_from<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     let value = if args.len() > 1 { vm.reg(args[1]) } else { JsValue::undefined() };
@@ -7784,31 +7362,6 @@ pub fn plain_date_since<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
 // Temporal.PlainMonthDay / Temporal.PlainYearMonth 对象地基：
 // 数字分量转换、槽对象构造、构造器与 getter/toString/toJSON。
 
-/// Temporal 数字分量转换（number-only 路径）：先 ToPrimitive(Number)——对象经
-/// valueOf/toString 取值；Symbol/BigInt → TypeError；NaN/±Inf → RangeError
-/// （undefined 与不可解析串都归 NaN，由此统一抛 RangeError）；其余截断取整。
-fn temporal_number_component<H: VmHost>(vm: &mut H, value: JsValue) -> Result<f64, JsValue> {
-    let primitive = oxide_runtime_api::to_primitive(value, oxide_runtime_api::ToPrimitiveHint::Number, vm)
-        .map_err(|error| native_engine_error(vm, &error))?;
-    if primitive.is_symbol() || primitive.is_bigint() {
-        return Err(crate::error::create_type_error(vm, "invalid number"));
-    }
-    let number = to_number(primitive);
-    if number.is_infinite() || number.is_nan() {
-        return Err(crate::error::create_range_error(vm, "invalid number"));
-    }
-    Ok(number.trunc())
-}
-
-/// ISO 年-月是否落在 PlainYearMonth 可表示范围（ISOYearMonthWithinLimits）：
-/// 年超 ±271821..=275760、或 -271821 年 3 月及以前、+275760 年 10 月及以后越界。
-fn iso_year_month_within_limits(year: i32, month: u32) -> bool {
-    if !(-271_821..=275_760).contains(&year) {
-        return false;
-    }
-    !((year == -271_821 && month < 4) || (year == 275_760 && month > 9))
-}
-
 /// 构造 PlainMonthDay 实例对象（槽 0-3 = 月/日/参考年/日历 ID）。
 /// from/toPlainDate 等返回新对象的成员使用；构造器走 receiver 初始化路径。
 fn make_plain_month_day<H: VmHost>(vm: &mut H, month: u32, day: u32, ref_year: i32, calendar: &str) -> NativeResult {
@@ -8080,55 +7633,6 @@ pub fn plain_year_month_era_year<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeRe
     NativeResult::Ok(JsValue::undefined())
 }
 
-/// toString 的 calendarName 选项取值（缺省 = auto；auto 与 never 的差异仅在注解）。
-enum ShowCalendar {
-    Auto,
-    Always,
-    Critical,
-    Never,
-}
-
-/// ISO 串尾部日历注解（FormatCalendarAnnotation）：never 与 auto+iso8601 为空；
-/// critical 前置 `!`；其余为 `[u-ca=…]`。
-fn calendar_annotation(calendar: &str, show: ShowCalendar) -> String {
-    match (show, calendar) {
-        (ShowCalendar::Never, _) => String::new(),
-        (ShowCalendar::Auto, "iso8601") => String::new(),
-        (ShowCalendar::Always, _) => format!("[u-ca={calendar}]"),
-        (ShowCalendar::Critical, _) => format!("[!u-ca={calendar}]"),
-        (ShowCalendar::Auto, _) => format!("[u-ca={calendar}]"),
-    }
-}
-
-/// 读并校验 toString 的 calendarName 选项：options 非对象 → TypeError；
-/// 值非字符串先 ToPrimitive(String) 转换（Symbol → TypeError）；
-/// 仅 auto/always/never/critical 合法（大小写敏感），否则 RangeError。
-fn temporal_to_show_calendar<H: VmHost>(vm: &mut H, args: &[u8]) -> Result<ShowCalendar, JsValue> {
-    let options = if args.len() > 1 { vm.reg(args[1]) } else { JsValue::undefined() };
-    if options.is_undefined() {
-        return Ok(ShowCalendar::Auto);
-    }
-    if !options.is_object() {
-        return Err(crate::error::create_type_error(vm, "options must be an object"));
-    }
-    let ptr = options.as_js_object_ptr();
-    if ptr.is_null() {
-        return Err(crate::error::create_type_error(vm, "options must be an object"));
-    }
-    let raw = temporal_option_value(vm, unsafe { &*ptr }, options, "calendarName")?;
-    if raw.is_undefined() {
-        return Ok(ShowCalendar::Auto);
-    }
-    let value = temporal_option_string(vm, raw)?;
-    match value.as_str() {
-        "always" => Ok(ShowCalendar::Always),
-        "critical" => Ok(ShowCalendar::Critical),
-        "never" => Ok(ShowCalendar::Never),
-        "auto" => Ok(ShowCalendar::Auto),
-        _ => Err(crate::error::create_range_error(vm, "invalid calendarName")),
-    }
-}
-
 /// PlainMonthDay ISO 串：always/critical 或非 iso8601 日历补参考年与日历注解；
 /// iso8601 日历的 auto/never 形保持裸 `MM-DD`。
 fn plain_month_day_iso_string(obj: &JsObject, show: ShowCalendar) -> String {
@@ -8564,42 +8068,6 @@ fn parse_year_month_string(input: &str) -> Result<(i32, u32), String> {
     Ok((year, month))
 }
 
-/// bag 日历解析：undefined → iso8601；字符串走宽松日历串解析（18-ID 白名单归一小写，
-/// 合法 ISO 日期-时间串归一 iso8601，含 YYYY-MM / MM-DD 部分日期）；
-/// PD/PDT/ZDT/PMD/PYM 实例 → 直读日历槽；其余对象与原始值 → TypeError。
-fn month_day_bag_calendar_id<H: VmHost>(vm: &mut H, value: JsValue) -> Result<String, JsValue> {
-    if value.is_undefined() {
-        return Ok("iso8601".to_string());
-    }
-    if value.is_string() {
-        let text = to_string(value);
-        return parse_temporal_calendar_string(&text)
-            .map_err(|_| crate::error::create_range_error(vm, "invalid calendar"));
-    }
-    if value.is_object() {
-        let ptr = value.as_js_object_ptr();
-        if !ptr.is_null() {
-            let obj = unsafe { &*ptr };
-            let slot = if obj.is_plain_date_obj() {
-                Some(3)
-            } else if obj.is_plain_date_time_obj() {
-                Some(4)
-            } else if obj.is_zoned_date_time_obj() {
-                Some(2)
-            } else if obj.is_plain_month_day_obj() || obj.is_plain_year_month_obj() {
-                Some(3)
-            } else {
-                None
-            };
-            if let Some(slot) = slot {
-                return Ok(get_calendar_id(obj, slot));
-            }
-        }
-        return Err(crate::error::create_type_error(vm, "invalid calendar"));
-    }
-    Err(crate::error::create_type_error(vm, "invalid calendar"))
-}
-
 /// `Temporal.PlainMonthDay.from(item[, options])`：ISO 串 / PMD 实例 / PD 实例 / 字段对象。
 /// 参考年恒 1972（串中年份与 bag year 均不入结果，year 仅供 overflow 月长判断）；
 /// options.overflow 在全部字段 Get 之后读取。