diff --git a/crates/oxide_builtins/src/array/common.rs b/crates/oxide_builtins/src/array/common.rs
index 9142ebbd..6ffe7e68 100644
--- a/crates/oxide_builtins/src/array/common.rs
+++ b/crates/oxide_builtins/src/array/common.rs
@@ -177,6 +177,14 @@ pub(crate) fn unit_string_value<H: VmHost>(vm: &mut H, unit: u16) -> JsValue {
     }
 }
 
+/// 索引位置存在性判定（规范 HasProperty：自身与原型链任一层命中即存在，
+/// 数组元素区 hole 视同缺失，TypedArray 整数索引按视图长度判在界）。
+pub(crate) fn arraylike_index_present<H: VmHost>(vm: &mut H, ptr: *mut JsObject, i: usize) -> bool {
+    // SAFETY: ptr 来自 this/参数对象，指向存活对象。
+    let key_si = vm.string_key_si(&i.to_string());
+    vm.has_property(unsafe { &*ptr }, key_si)
+}
+
 /// 元素读取失败时直接把异常作为 NativeResult::Err 返回。
 macro_rules! arraylike_get_or_err {
     ($vm:expr, $ptr:expr, $i:expr) => {
diff --git a/crates/oxide_builtins/src/array/element.rs b/crates/oxide_builtins/src/array/element.rs
index 6434c3d5..11810858 100644
--- a/crates/oxide_builtins/src/array/element.rs
+++ b/crates/oxide_builtins/src/array/element.rs
@@ -9,8 +9,9 @@ use crate::builtins_debug;
 use crate::builtins_error;
 
 use super::common::{
-    array_ptr, array_type_error, arraylike_get, arraylike_get_or_err, check_array_create_len, clamp_relative,
-    create_new_array, get_this_array_ref, get_this_arraylike, js_array_index, to_integer_or_infinity_bounded,
+    array_ptr, array_type_error, arraylike_get, arraylike_get_or_err, arraylike_index_present, check_array_create_len,
+    clamp_relative, create_new_array, get_this_array_ref, get_this_arraylike, js_array_index,
+    to_integer_or_infinity_bounded,
 };
 use super::from::{array_species_create, create_data_property_or_throw, from_engine_error};
 
@@ -125,28 +126,38 @@ pub fn array_slice<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         Ok(p) => p,
         Err(err) => return NativeResult::Err(err),
     };
-    // HasProperty + Get + CreateDataPropertyOrThrow 逐元素拷贝。
+    // HasProperty + Get + CreateDataPropertyOrThrow 逐元素拷贝；洞位只在真数组
+    // 目标上留洞（目标预填 present-undefined，须显式置洞）。
     let mut k = start;
     let mut out_idx = 0usize;
+    let mut holes: Vec<usize> = Vec::new();
     while k < end {
-        let key_str = vm.new_string(&k.to_string());
-        let key_si = vm.property_key_si(key_str);
-        if vm.resolve_property(unsafe { &*arr_ptr }, key_si).is_some() {
+        if arraylike_index_present(vm, arr_ptr, k) {
             let elem = arraylike_get_or_err!(vm, arr_ptr, k);
             let out_key = vm.new_string(&out_idx.to_string());
             let out_key_si = vm.property_key_si(out_key);
             if let Err(err) = create_data_property_or_throw(vm, unsafe { &mut *a_ptr }, out_key_si, elem) {
                 return NativeResult::Err(err);
             }
-            out_idx += 1;
+        } else {
+            holes.push(out_idx);
         }
+        out_idx += 1;
         k += 1;
     }
-    // 收尾 Set(A, "length", final)：普通 Set 语义（可触发继承 setter/异常）。
+    // 收尾 Set(A, "length", final)：终长 = 区间长度（end - start），洞位计入；
+    // 普通 Set 语义（可触发继承 setter/异常）。
     let a_val = JsValue::from_js_object(a_ptr);
+    if unsafe { &*a_ptr }.is_array() {
+        for p in holes {
+            unsafe {
+                (*a_ptr).mark_hole_at(p);
+            }
+        }
+    }
     let length_key = vm.new_string("length");
     let length_si = vm.property_key_si(length_key);
-    if let Err(err) = vm.ordinary_set(unsafe { &mut *a_ptr }, length_si, js_array_index(out_idx), a_val, true) {
+    if let Err(err) = vm.ordinary_set(unsafe { &mut *a_ptr }, length_si, js_array_index(count), a_val, true) {
         return NativeResult::Err(from_engine_error(vm, &err));
     }
     NativeResult::Ok(JsValue::from_js_object(a_ptr))
@@ -225,12 +236,19 @@ pub fn array_concat<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         Ok(v) => v,
         Err(e) => return NativeResult::Err(e),
     };
+    // this 与数组实参的洞位按缺失复制：结果对应位留洞（记录洞下标，收尾置洞）。
     let mut all: Vec<JsValue> = Vec::new();
+    let mut holes: Vec<usize> = Vec::new();
     if let Err(err) = check_array_create_len(vm, n) {
         return NativeResult::Err(err);
     }
     for i in 0..n {
-        all.push(arraylike_get_or_err!(vm, arr_ptr, i));
+        if arraylike_index_present(vm, arr_ptr, i) {
+            all.push(arraylike_get_or_err!(vm, arr_ptr, i));
+        } else {
+            holes.push(all.len());
+            all.push(JsValue::undefined());
+        }
     }
     for &arg_reg in args.iter().skip(1) {
         let val = vm.reg(arg_reg);
@@ -239,10 +257,16 @@ pub fn array_concat<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
             if !o_ptr.is_null() {
                 let o = unsafe { &*o_ptr };
                 let on = o.prop_count() as usize;
-                // 真数组时展开元素。
+                // 真数组时展开元素（洞位同样留洞）。
                 if o.is_array() && on > 0 {
+                    let dense = o.array_elements_meta_vec().is_none();
                     for i in 0..on {
-                        all.push(o.get_prop_at(i));
+                        if dense || !o.prop_meta_at(i).is_some_and(|m| m.is_hole()) {
+                            all.push(o.get_prop_at(i));
+                        } else {
+                            holes.push(all.len());
+                            all.push(JsValue::undefined());
+                        }
                     }
                     continue;
                 }
@@ -255,6 +279,9 @@ pub fn array_concat<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         for (i, val) in all.iter().enumerate() {
             (*new_arr).set_prop_at(i, *val);
         }
+        for h in holes {
+            (*new_arr).mark_hole_at(h);
+        }
         (*new_arr).set_prop_count(all.len());
     }
     NativeResult::Ok(JsValue::from_js_object(new_arr))
@@ -329,6 +356,10 @@ pub fn array_index_of<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         0
     };
     for i in from_index..n {
+        // 洞位不参与比较：HasProperty 缺失即跳过（洞不是 undefined 元素）。
+        if !arraylike_index_present(vm, ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, ptr, i);
         if oxide_runtime_api::strict_equality(elem, target) {
             return NativeResult::Ok(js_array_index(i));
@@ -426,8 +457,15 @@ pub fn array_flat<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
                     let o = unsafe { &*ptr };
                     if o.is_array() {
                         seen.push(ptr);
+                        // 嵌套展开丢弃洞位：flat 结果恒为紧凑数组。
                         let on = o.prop_count() as usize;
-                        let sub: Vec<JsValue> = (0..on).map(|i| o.get_prop_at(i)).collect();
+                        let dense = o.array_elements_meta_vec().is_none();
+                        let mut sub: Vec<JsValue> = Vec::with_capacity(on);
+                        for i in 0..on {
+                            if dense || !o.prop_meta_at(i).is_some_and(|m| m.is_hole()) {
+                                sub.push(o.get_prop_at(i));
+                            }
+                        }
                         let flat = flatten(&sub, remaining_depth - 1, seen);
                         seen.pop();
                         out.extend(flat);
@@ -440,7 +478,14 @@ pub fn array_flat<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         out
     }
 
-    let all: Vec<JsValue> = (0..n).map(|i| arr.get_prop_at(i)).collect();
+    // 顶层同样丢弃洞位（接收者恒为真数组，元数据表判洞免字符串键）。
+    let dense = arr.array_elements_meta_vec().is_none();
+    let mut all: Vec<JsValue> = Vec::with_capacity(n);
+    for i in 0..n {
+        if dense || !arr.prop_meta_at(i).is_some_and(|m| m.is_hole()) {
+            all.push(arr.get_prop_at(i));
+        }
+    }
     let mut seen = vec![arr_ptr];
     let flat = flatten(&all, depth, &mut seen);
     let new_arr = create_new_array(vm, flat.len());
@@ -689,6 +734,10 @@ pub fn array_last_index_of<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         return NativeResult::Ok(JsValue::int(-1));
     }
     for i in (0..=from_index_isize as usize).rev() {
+        // 洞位不参与比较：HasProperty 缺失即跳过（洞不是 undefined 元素）。
+        if !arraylike_index_present(vm, ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, ptr, i);
         if oxide_runtime_api::strict_equality(elem, search) {
             return NativeResult::Ok(js_array_index(i));
diff --git a/crates/oxide_builtins/src/array/iterate.rs b/crates/oxide_builtins/src/array/iterate.rs
index ad4aec1a..8e849699 100644
--- a/crates/oxide_builtins/src/array/iterate.rs
+++ b/crates/oxide_builtins/src/array/iterate.rs
@@ -8,8 +8,9 @@ use crate::builtins_debug;
 use crate::builtins_error;
 
 use super::common::{
-    array_ptr_len3, array_type_error, arraylike_get, arraylike_get_or_err, check_array_create_len, create_new_array,
-    get_this_arraylike, invoke_native_callback, js_array_index, require_callback, unexpected_tail_call_error,
+    array_ptr_len3, array_type_error, arraylike_get, arraylike_get_or_err, arraylike_index_present,
+    check_array_create_len, create_new_array, get_this_arraylike, invoke_native_callback, js_array_index,
+    require_callback, unexpected_tail_call_error,
 };
 
 /// `Array.prototype.forEach(callback, thisArg)`：对每个元素调用 callback，返回 undefined。
@@ -26,6 +27,10 @@ pub fn array_for_each<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     };
     let this_val = if args.len() > 2 { vm.reg(args[2]) } else { JsValue::undefined() };
     for i in 0..n {
+        // 洞位跳过：回调不得在缺失索引上触发。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i), o_val]) {
             NativeResult::Ok(_) => {}
@@ -54,6 +59,13 @@ pub fn array_map<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         return NativeResult::Err(err);
     }
     for i in 0..n {
+        // 洞位跳过回调，并在结果对应位留洞（结果数组预填 present-undefined，须显式置洞）。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            unsafe {
+                (*new_arr).mark_hole_at(i);
+            }
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i), o_val]) {
             NativeResult::Ok(mapped) => unsafe {
@@ -91,6 +103,10 @@ pub fn array_filter<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         return NativeResult::Err(err);
     }
     for i in 0..n {
+        // 洞位跳过：结果保持紧凑，不复制缺失索引。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i), o_val]) {
             NativeResult::Ok(result_val) => {
@@ -118,10 +134,6 @@ pub fn array_reduce<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     builtins_debug!("Array.prototype.reduce called with {} args", args.len());
     let (arr_ptr, n, _is_array) = array_ptr_len3!(vm, args);
     let o_val = vm.reg(args[0]);
-    if n == 0 && args.len() < 3 {
-        builtins_error!("Array.prototype.reduce: invalid receiver");
-        return NativeResult::Err(array_type_error(vm, "Reduce of empty array with no initial value"));
-    }
     if args.len() < 2 {
         builtins_error!("Array.prototype.reduce: invalid receiver");
         return NativeResult::Err(array_type_error(vm, "callback is not a function"));
@@ -140,11 +152,30 @@ pub fn array_reduce<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         accumulator = vm.reg(args[2]);
         start_idx = 0;
     } else {
-        accumulator = arraylike_get_or_err!(vm, arr_ptr, 0);
-        start_idx = 1;
+        // FindFirstKey：无初值时取首个存在索引作累加器；全洞（含空数组）抛 TypeError。
+        let mut found = None;
+        for i in 0..n {
+            if arraylike_index_present(vm, arr_ptr, i) {
+                found = Some(i);
+                break;
+            }
+        }
+        let idx = match found {
+            Some(idx) => idx,
+            None => {
+                builtins_error!("Array.prototype.reduce: invalid receiver");
+                return NativeResult::Err(array_type_error(vm, "Reduce of empty array with no initial value"));
+            }
+        };
+        accumulator = arraylike_get_or_err!(vm, arr_ptr, idx);
+        start_idx = idx + 1;
     }
     let this_val = JsValue::undefined();
     for i in start_idx..n {
+        // 洞位跳过：累加器保持上一 present 元素的结果。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[accumulator, elem, js_array_index(i), o_val]) {
             NativeResult::Ok(result) => accumulator = result,
@@ -217,6 +248,10 @@ pub fn array_some<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     };
     let this_val = if args.len() > 2 { vm.reg(args[2]) } else { JsValue::undefined() };
     for i in 0..n {
+        // 洞位跳过：回调不得在缺失索引上触发。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i), o_val]) {
             NativeResult::Ok(result_val) => {
@@ -255,6 +290,10 @@ pub fn array_every<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     };
     let this_val = if args.len() > 2 { vm.reg(args[2]) } else { JsValue::undefined() };
     for i in 0..n {
+        // 洞位跳过：回调不得在缺失索引上触发。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i), o_val]) {
             NativeResult::Ok(result_val) => {
@@ -297,6 +336,10 @@ pub fn array_flat_map<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         return NativeResult::Err(err);
     }
     for i in 0..n {
+        // 洞位跳过：回调不得在缺失索引上触发。
+        if !arraylike_index_present(vm, arr_ptr, i) {
+            continue;
+        }
         let elem = arraylike_get_or_err!(vm, arr_ptr, i);
         match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i), o_val]) {
             NativeResult::Ok(result) => {
@@ -305,9 +348,13 @@ pub fn array_flat_map<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
                     if !r_ptr.is_null() {
                         let r = unsafe { &*r_ptr };
                         if r.is_array() {
+                            // 嵌套数组展开丢弃洞位：结果为紧凑数组。
                             let rn = r.prop_count() as usize;
+                            let dense = r.array_elements_meta_vec().is_none();
                             for j in 0..rn {
-                                flat.push(r.get_prop_at(j));
+                                if dense || !r.prop_meta_at(j).is_some_and(|m| m.is_hole()) {
+                                    flat.push(r.get_prop_at(j));
+                                }
                             }
                             continue;
                         }
@@ -394,8 +441,8 @@ pub fn array_find_last<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     };
     let this_val = if args.len() > 2 { vm.reg(args[2]) } else { JsValue::undefined() };
     for i in (0..n).rev() {
-        let elem = unsafe { (*arr_ptr).get_prop_at(i) };
-        match invoke_native_callback(vm, callback_val, this_val, &[elem, JsValue::int(i), o_val]) {
+        let elem = arraylike_get_or_err!(vm, arr_ptr, i as usize);
+        match invoke_native_callback(vm, callback_val, this_val, &[elem, js_array_index(i as usize), o_val]) {
             NativeResult::Ok(r) => {
                 if oxide_runtime_api::to_boolean(r) {
                     return NativeResult::Ok(elem);
@@ -433,15 +480,35 @@ pub fn array_reduce_right<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     let (mut acc, start_idx): (JsValue, i32) = if args.len() > 2 {
         (vm.reg(args[2]), n as i32 - 1)
     } else {
-        if n == 0 {
-            builtins_error!("Array.prototype.reduceRight: invalid receiver");
-            return NativeResult::Err(array_type_error(vm, "Reduce of empty array with no initial value"));
+        // FindFirstKey 自尾：无初值时取末尾首个存在索引作累加器；全洞抛 TypeError。
+        let mut found = None;
+        for i in (0..n).rev() {
+            if arraylike_index_present(vm, arr_ptr, i) {
+                found = Some(i);
+                break;
+            }
         }
-        (unsafe { (*arr_ptr).get_prop_at(n - 1) }, n as i32 - 2)
+        let idx = match found {
+            Some(idx) => idx,
+            None => {
+                builtins_error!("Array.prototype.reduceRight: invalid receiver");
+                return NativeResult::Err(array_type_error(vm, "Reduce of empty array with no initial value"));
+            }
+        };
+        (arraylike_get_or_err!(vm, arr_ptr, idx), idx as i32 - 1)
     };
     for i in (0..=start_idx).rev() {
-        let elem = unsafe { (*arr_ptr).get_prop_at(i as usize) };
-        match invoke_native_callback(vm, callback_val, JsValue::undefined(), &[acc, elem, JsValue::int(i), o_val]) {
+        // 洞位跳过：累加器保持上一 present 元素的结果。
+        if !arraylike_index_present(vm, arr_ptr, i as usize) {
+            continue;
+        }
+        let elem = arraylike_get_or_err!(vm, arr_ptr, i as usize);
+        match invoke_native_callback(
+            vm,
+            callback_val,
+            JsValue::undefined(),
+            &[acc, elem, js_array_index(i as usize), o_val],
+        ) {
             NativeResult::Ok(r) => acc = r,
             NativeResult::Err(err) => {
                 builtins_error!("Array.prototype.reduceRight: invalid receiver");
diff --git a/crates/oxide_builtins/src/array/sort_iterator.rs b/crates/oxide_builtins/src/array/sort_iterator.rs
index d9a99b40..e7382110 100644
--- a/crates/oxide_builtins/src/array/sort_iterator.rs
+++ b/crates/oxide_builtins/src/array/sort_iterator.rs
@@ -73,7 +73,8 @@ pub(crate) fn parse_sort_comparator<H: VmHost>(vm: &mut H, candidate: JsValue) -
 /// 原地排序数组元素并返回原数组（`Array.prototype.sort`）。
 ///
 /// 未提供比较回调时按 ToString 结果的字符串字典序排序；底层 `sort_by` 为稳定
-/// 排序，比较结果相等（含 NaN）的元素保持原有相对次序。
+/// 排序，比较结果相等（含 NaN）的元素保持原有相对次序。洞位不参与比较：
+/// present 值稳定排序后自索引 0 紧凑写回，尾部空位转为洞。
 ///
 /// # 边界与前提
 /// - 接收者不是数组时抛 TypeError；
@@ -82,7 +83,13 @@ pub fn array_sort<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     builtins_debug!("Array.prototype.sort called with {} args", args.len());
     let arr_ptr = array_ptr!(vm, args);
     let len = unsafe { (*arr_ptr).prop_count() as usize };
-    let mut vals: Vec<JsValue> = (0..len).map(|i| unsafe { (*arr_ptr).get_prop_at(i) }).collect();
+    // 洞位不参与比较：只收集 present 元素（接收者恒为真数组，元数据表判洞免字符串键）。
+    let arr_ref = unsafe { &*arr_ptr };
+    let dense = arr_ref.array_elements_meta_vec().is_none();
+    let mut vals: Vec<JsValue> = (0..len)
+        .filter(|&i| dense || !arr_ref.prop_meta_at(i).is_some_and(|m| m.is_hole()))
+        .map(|i| arr_ref.get_prop_at(i))
+        .collect();
     let comparator = if args.len() > 1 {
         match parse_sort_comparator(vm, vm.reg(args[1])) {
             Ok(c) => c,
@@ -98,10 +105,14 @@ pub fn array_sort<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         builtins_error!("Array.prototype.sort: invalid receiver");
         return NativeResult::Err(err);
     }
+    // present 值稳定排序后从索引 0 紧凑写回，尾部空位转为洞。
     let arr = unsafe { &mut *arr_ptr };
     for (i, &v) in vals.iter().enumerate() {
         arr.set_prop_at(i, v);
     }
+    for i in vals.len()..len {
+        arr.mark_hole_at(i);
+    }
     NativeResult::Ok(vm.reg(args[0]))
 }
 
diff --git a/crates/oxide_builtins/src/typed_array.rs b/crates/oxide_builtins/src/typed_array.rs
index 0f29ac1d..4f2079c7 100644
--- a/crates/oxide_builtins/src/typed_array.rs
+++ b/crates/oxide_builtins/src/typed_array.rs
@@ -233,7 +233,7 @@ pub fn typed_array_element_get<H: VmHost>(vm: &mut H, obj: &JsObject, index: u32
 
 /// 若对象是 TypedArray 且属性键是整数索引，返回 `(索引, 视图长度)`；否则 `None`。
 /// 供 VM 在 receiver ≠ TA 时裁决整数索引的写前语义（越界直接返回，界内落到 receiver）。
-pub fn typed_array_integer_index<H: VmHost>(vm: &mut H, obj: &JsObject, prop_name_si: u32) -> Option<(usize, usize)> {
+pub fn typed_array_integer_index<H: VmHost>(vm: &H, obj: &JsObject, prop_name_si: u32) -> Option<(usize, usize)> {
     let ptr = typed_array_data_ptr(obj)?;
     if ptr.is_null() {
         return None;
diff --git a/crates/oxide_runtime_api/src/host.rs b/crates/oxide_runtime_api/src/host.rs
index 937ae1f3..10a30b01 100644
--- a/crates/oxide_runtime_api/src/host.rs
+++ b/crates/oxide_runtime_api/src/host.rs
@@ -103,6 +103,9 @@ pub trait VmHost {
     /// 供建键入口（fromEntries/json/rest excluded）与 `property_key_si` 的字符串分支统一口径。
     fn string_key_si(&mut self, s: &str) -> u32;
     fn resolve_property(&self, obj: &JsObject, prop_name_si: u32) -> Option<JsValue>;
+    /// 存在性判定（规范 HasProperty）：自身与原型链任一层 P 为自有属性即存在；
+    /// 数组元素区 hole 视同缺失，TypedArray 整数索引按视图长度判在界。
+    fn has_property(&self, obj: &JsObject, prop_name_si: u32) -> bool;
     fn get_own_property_slot(&self, obj: &JsObject, prop_name_si: u32) -> Option<u32>;
 
     // 属性访问
diff --git a/crates/oxide_vm/src/vm/props.rs b/crates/oxide_vm/src/vm/props.rs
index 1b7d493b..25ae1f09 100644
--- a/crates/oxide_vm/src/vm/props.rs
+++ b/crates/oxide_vm/src/vm/props.rs
@@ -212,6 +212,43 @@ impl Vm {
         None
     }
 
+    /// 存在性判定（规范 HasProperty）：自身与原型链逐级检查，任一层 P 为自有
+    /// 属性即存在。数组 length 虚拟属性恒存在；数组元素区 hole 视同缺失；
+    /// TypedArray 整数索引按视图长度判在界；其余按 shape 槽判定。
+    ///
+    /// 与 `resolve_property` 的差异：原型链上每层都检查数组元素区与 TypedArray
+    /// 元素（`resolve_property` 只在顶层检查元素区，链上仅走 shape 槽），
+    /// 继承自父数组/TypedArray 的索引属性在此判存在。
+    pub(crate) fn has_property(&self, obj: &JsObject, prop_name_si: u32) -> bool {
+        let length_si = self.length_si;
+        let mut current = Some(obj);
+        let mut depth = 0usize;
+        while let Some(obj) = current {
+            if obj.is_array() && prop_name_si == length_si {
+                return true;
+            }
+            if obj.is_typed_array_obj() {
+                if let Some((index, len)) =
+                    oxide_builtins::typed_array::typed_array_integer_index(self, obj, prop_name_si)
+                {
+                    if index < len {
+                        return true;
+                    }
+                }
+            }
+            if self.get_own_property_slot(obj, prop_name_si).is_some() {
+                return true;
+            }
+            if depth >= MAX_PROTO_CHAIN_DEPTH {
+                break;
+            }
+            depth += 1;
+            let proto = obj.proto();
+            current = proto.is_object().then(|| unsafe { &*proto.as_js_object_ptr() });
+        }
+        false
+    }
+
     /// 查找自身属性槽下标：数组 length 虚拟属性返回 `None`，元素区返回下标，
     /// shape 槽按数组（元素区之后偏移）与普通对象（槽位即下标）各自定位；
     /// 未命中的槽返回 `None`。
diff --git a/crates/oxide_vm/src/vm/vmhost.rs b/crates/oxide_vm/src/vm/vmhost.rs
index 419c590b..1f163922 100644
--- a/crates/oxide_vm/src/vm/vmhost.rs
+++ b/crates/oxide_vm/src/vm/vmhost.rs
@@ -87,6 +87,9 @@ impl oxide_runtime_api::VmHost for Vm {
     fn resolve_property(&self, obj: &JsObject, prop_name_si: u32) -> Option<JsValue> {
         self.resolve_property(obj, prop_name_si)
     }
+    fn has_property(&self, obj: &JsObject, prop_name_si: u32) -> bool {
+        self.has_property(obj, prop_name_si)
+    }
     fn get_own_property_slot(&self, obj: &JsObject, prop_name_si: u32) -> Option<u32> {
         self.get_own_property_slot(obj, prop_name_si)
     }
diff --git a/crates/oxide_vm/tests/array_length_set_tests.rs b/crates/oxide_vm/tests/array_length_set_tests.rs
index f28bd901..73d6003c 100644
--- a/crates/oxide_vm/tests/array_length_set_tests.rs
+++ b/crates/oxide_vm/tests/array_length_set_tests.rs
@@ -263,3 +263,60 @@ fn new_array_holes_pop_shift() {
     assert_eq!(eval_str("var a=new Array(1); var p=a.pop(); (p===undefined)+':'+a.length"), "true:0");
     assert_eq!(eval_str("var a=new Array(1); var s=a.shift(); (s===undefined)+':'+a.length"), "true:0");
 }
+
+#[test]
+fn read_paths_skip_holes_per_spec() {
+    // iterate 族：洞位不触发回调；map 结果在源洞位留洞、长度不变。
+    assert_eq!(eval_str("var n=0; new Array(2).forEach(function(){n++;}); ''+n"), "0");
+    assert_eq!(
+        eval_str("var n=0; var r=[1,,3].map(function(x){n++;return x;}); n+':'+(1 in r)+':'+r.length"),
+        "2:false:3"
+    );
+    assert_eq!(
+        eval_str("var r=new Array(3).map(function(x){return x;}); (0 in r)+':'+r.length"),
+        "false:3"
+    );
+    assert_eq!(eval_str("new Array(2).filter(function(){return true;}).length"), "0");
+    // reduce/reduceRight：无初值取首个/末尾 present 位作累加器，洞位跳过；全洞抛 TypeError。
+    assert_eq!(
+        eval_str("[1,,].reduce(function(a,b){return b;})+':'+(function(){try{new Array(1).reduce(function(){});return 'no-throw';}catch(e){return e.name;}})()"),
+        "1:TypeError"
+    );
+    assert_eq!(
+        eval_str("[,1,2].reduceRight(function(a,b){return a+b;})+':'+(function(){try{new Array(1).reduceRight(function(){});return 'no-throw';}catch(e){return e.name;}})()"),
+        "3:TypeError"
+    );
+    // flatMap：洞位不触发回调；嵌套数组展开丢弃洞位（紧凑结果）。
+    assert_eq!(
+        eval_str("new Array(1).flatMap(function(x){return [x];}).length+':'+[1].flatMap(function(){return [1,,3];}).join(',')+':'+[1].flatMap(function(){return [1,,3];}).length"),
+        "0:1,3:2"
+    );
+    // indexOf/lastIndexOf：洞位不参与比较。
+    assert_eq!(eval_str("[1,,3].indexOf(undefined)+':'+[1,,3].lastIndexOf(undefined)"), "-1:-1");
+    // slice：终长 = end - start；源洞位在结果中留洞。
+    assert_eq!(
+        eval_str("new Array(3).slice().length+':'+[1,,3].slice(0,2).length+':'+(1 in [1,,3].slice(0,2))"),
+        "3:2:false"
+    );
+    // concat：this 与数组实参的洞位均在结果中保洞。
+    assert_eq!(
+        eval_str("[1].concat([,2]).length+':'+(1 in [1].concat([,2]))+':'+[1].concat(new Array(1)).length"),
+        "3:false:2"
+    );
+    // flat：顶层与嵌套洞位均丢弃（紧凑结果）。
+    assert_eq!(eval_str("[,1].flat().length+':'+[1,[2,,3],4].flat().join(',')"), "1:1,2,3,4");
+    // sort：洞位不参与比较；present 值紧凑写回，尾部转洞。
+    assert_eq!(
+        eval_str("var a=[,1,3,2].sort(); (0 in a)+':'+(3 in a)+':'+a.join(',')"),
+        "true:false:1,2,3,"
+    );
+    assert_eq!(
+        eval_str("var b=[5,,1,3].sort(function(x,y){return x-y;}); b.join(',')+':'+(3 in b)"),
+        "1,3,5,:false"
+    );
+    // 防过度门控：find 族无门控（洞位照常调回调）、includes 无门控（洞 Get 得 undefined）。
+    assert_eq!(
+        eval_str("[,1].findIndex(function(){return true;})+':'+[1,,3].includes(undefined)+':'+[,1].findIndex(function(x){return x===1;})"),
+        "0:true:1"
+    );
+}
diff --git a/crates/oxide_vm/tests/builtins_array_tests.rs b/crates/oxide_vm/tests/builtins_array_tests.rs
index a2212352..cef15bfe 100644
--- a/crates/oxide_vm/tests/builtins_array_tests.rs
+++ b/crates/oxide_vm/tests/builtins_array_tests.rs
@@ -392,19 +392,19 @@ fn array_fill_single() {
 }
 
 #[test]
-fn array_iteration_hole_reads_undefined() {
-    // 稀疏数组（字面量空洞 / delete）元素读取落到 undefined：引擎对 hole 不跳过
-    // 回调而是读 undefined（pre-existing 语义，直读 fast path 与慢路径一致）。
+fn array_iteration_holes_skipped_per_spec() {
+    // 稀疏数组（字面量空洞 / delete）：洞位不触发回调，map 结果在洞位留洞，
+    // join 把洞位渲染为空串。
     let (vm, result) = eval("[10,,30].map(x=>x*2).join(',')").unwrap();
-    assert_eq!(to_str(&vm, result), "20,NaN,60");
+    assert_eq!(to_str(&vm, result), "20,,60");
 
-    // delete 产生的 hole 经 map 读 undefined，不残留洞前值。
+    // delete 产生的洞位经 map 同样跳过，不残留洞前值。
     let (vm, result) = eval("var a=[1,2,3]; delete a[1]; a.map(x=>x+1).join(',')").unwrap();
-    assert_eq!(to_str(&vm, result), "2,NaN,4");
+    assert_eq!(to_str(&vm, result), "2,,4");
 
-    // reduce 对 hole 累加 undefined。
+    // reduce 跳过洞位：初值直接接到首个 present 元素。
     let (vm, result) = eval("var a=[1,,3]; a.reduce((s,x)=>s+','+x,'')").unwrap();
-    assert_eq!(to_str(&vm, result), ",1,undefined,3");
+    assert_eq!(to_str(&vm, result), ",1,3");
 }
 
 #[test]