240 lines
10 KiB
C++
240 lines
10 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Function.h>
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#include <LibJS/Runtime/Array.h>
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#include <LibJS/Runtime/Completion.h>
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#include <LibJS/Runtime/Error.h>
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#include <LibJS/Runtime/GlobalObject.h>
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namespace JS {
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// 10.4.2.2 ArrayCreate ( length [ , proto ] ), https://tc39.es/ecma262/#sec-arraycreate
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Array* Array::create(GlobalObject& global_object, size_t length, Object* prototype)
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{
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auto& vm = global_object.vm();
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if (length > NumericLimits<u32>::max()) {
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vm.throw_exception<RangeError>(global_object, ErrorType::InvalidLength, "array");
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return nullptr;
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}
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if (!prototype)
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prototype = global_object.array_prototype();
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auto* array = global_object.heap().allocate<Array>(global_object, *prototype);
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MUST(array->internal_define_own_property(vm.names.length, { .value = Value(length), .writable = true, .enumerable = false, .configurable = false }));
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return array;
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}
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// 7.3.17 CreateArrayFromList ( elements ), https://tc39.es/ecma262/#sec-createarrayfromlist
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Array* Array::create_from(GlobalObject& global_object, Vector<Value> const& elements)
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{
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// 1. Assert: elements is a List whose elements are all ECMAScript language values.
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// 2. Let array be ! ArrayCreate(0).
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auto* array = Array::create(global_object, 0);
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// 3. Let n be 0.
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// 4. For each element e of elements, do
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for (u32 n = 0; n < elements.size(); ++n) {
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// a. Perform ! CreateDataPropertyOrThrow(array, ! ToString(𝔽(n)), e).
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MUST(array->create_data_property_or_throw(n, elements[n]));
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// b. Set n to n + 1.
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}
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// 5. Return array.
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return array;
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}
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Array::Array(Object& prototype)
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: Object(prototype)
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{
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}
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Array::~Array()
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{
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}
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// 10.4.2.4 ArraySetLength ( A, Desc ), https://tc39.es/ecma262/#sec-arraysetlength
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bool Array::set_length(PropertyDescriptor const& property_descriptor)
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{
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auto& global_object = this->global_object();
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auto& vm = this->vm();
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// 1. If Desc.[[Value]] is absent, then
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// a. Return OrdinaryDefineOwnProperty(A, "length", Desc).
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// 2. Let newLenDesc be a copy of Desc.
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// NOTE: Handled by step 16
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size_t new_length = indexed_properties().array_like_size();
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if (property_descriptor.value.has_value()) {
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// 3. Let newLen be ? ToUint32(Desc.[[Value]]).
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new_length = property_descriptor.value->to_u32(global_object);
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if (vm.exception())
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return {};
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// 4. Let numberLen be ? ToNumber(Desc.[[Value]]).
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auto number_length = property_descriptor.value->to_number(global_object);
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if (vm.exception())
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return {};
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// 5. If newLen is not the same value as numberLen, throw a RangeError exception.
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if (new_length != number_length.as_double()) {
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vm.throw_exception<RangeError>(global_object, ErrorType::InvalidLength, "array");
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return {};
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}
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}
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// 6. Set newLenDesc.[[Value]] to newLen.
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// 7. Let oldLenDesc be OrdinaryGetOwnProperty(A, "length").
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// 8. Assert: ! IsDataDescriptor(oldLenDesc) is true.
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// 9. Assert: oldLenDesc.[[Configurable]] is false.
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// 10. Let oldLen be oldLenDesc.[[Value]].
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// 11. If newLen ≥ oldLen, then
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// a. Return OrdinaryDefineOwnProperty(A, "length", newLenDesc).
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// 12. If oldLenDesc.[[Writable]] is false, return false.
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// NOTE: Handled by step 16
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// 13. If newLenDesc.[[Writable]] is absent or has the value true, let newWritable be true.
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// 14. Else,
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// a. NOTE: Setting the [[Writable]] attribute to false is deferred in case any elements cannot be deleted.
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// b. Let newWritable be false.
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auto new_writable = property_descriptor.writable.value_or(true);
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// c. Set newLenDesc.[[Writable]] to true.
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// 15. Let succeeded be ! OrdinaryDefineOwnProperty(A, "length", newLenDesc).
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// 16. If succeeded is false, return false.
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// NOTE: Because the length property does not actually exist calling OrdinaryDefineOwnProperty
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// will result in unintended behavior, so instead we only implement here the small subset of
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// checks performed inside of it that would have mattered to us:
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// 10.1.6.3 ValidateAndApplyPropertyDescriptor ( O, P, extensible, Desc, current ), https://tc39.es/ecma262/#sec-validateandapplypropertydescriptor
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// 4. If current.[[Configurable]] is false, then
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// a. If Desc.[[Configurable]] is present and its value is true, return false.
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if (property_descriptor.configurable.has_value() && *property_descriptor.configurable)
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return false;
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// b. If Desc.[[Enumerable]] is present and ! SameValue(Desc.[[Enumerable]], current.[[Enumerable]]) is false, return false.
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if (property_descriptor.enumerable.has_value() && *property_descriptor.enumerable)
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return false;
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// 6. Else if ! SameValue(! IsDataDescriptor(current), ! IsDataDescriptor(Desc)) is false, then
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if (property_descriptor.is_accessor_descriptor()) {
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// a. If current.[[Configurable]] is false, return false.
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return false;
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}
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// 7. Else if IsDataDescriptor(current) and IsDataDescriptor(Desc) are both true, then
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// a. If current.[[Configurable]] is false and current.[[Writable]] is false, then
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if (!m_length_writable) {
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// i. If Desc.[[Writable]] is present and Desc.[[Writable]] is true, return false.
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if (property_descriptor.writable.has_value() && *property_descriptor.writable)
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return false;
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// ii. If Desc.[[Value]] is present and SameValue(Desc.[[Value]], current.[[Value]]) is false, return false.
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if (new_length != indexed_properties().array_like_size())
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return false;
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}
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// 17. For each own property key P of A that is an array index, whose numeric value is greater than or equal to newLen, in descending numeric index order, do
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// a. Let deleteSucceeded be ! A.[[Delete]](P).
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// b. If deleteSucceeded is false, then
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// i. Set newLenDesc.[[Value]] to ! ToUint32(P) + 1𝔽.
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bool success = indexed_properties().set_array_like_size(new_length);
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// ii. If newWritable is false, set newLenDesc.[[Writable]] to false.
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// iii. Perform ! OrdinaryDefineOwnProperty(A, "length", newLenDesc).
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// NOTE: Handled by step 18
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// 18. If newWritable is false, then
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// a. Set succeeded to ! OrdinaryDefineOwnProperty(A, "length", PropertyDescriptor { [[Writable]]: false }).
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// b. Assert: succeeded is true.
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if (!new_writable)
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m_length_writable = false;
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// NOTE: Continuation of step #17
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// iv. Return false.
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if (!success)
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return false;
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// 19. Return true.
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return true;
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}
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// NON-STANDARD: Used to return the value of the ephemeral length property
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ThrowCompletionOr<Optional<PropertyDescriptor>> Array::internal_get_own_property(PropertyName const& property_name) const
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{
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auto& vm = this->vm();
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if (property_name.is_string() && property_name.as_string() == vm.names.length.as_string())
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return { PropertyDescriptor { .value = Value(indexed_properties().array_like_size()), .writable = m_length_writable, .enumerable = false, .configurable = false } };
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return Object::internal_get_own_property(property_name);
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}
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// 10.4.2.1 [[DefineOwnProperty]] ( P, Desc ), https://tc39.es/ecma262/#sec-array-exotic-objects-defineownproperty-p-desc
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ThrowCompletionOr<bool> Array::internal_define_own_property(PropertyName const& property_name, PropertyDescriptor const& property_descriptor)
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{
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auto& vm = this->vm();
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// 1. Assert: IsPropertyKey(P) is true.
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VERIFY(property_name.is_valid());
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// 2. If P is "length", then
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if (property_name.is_string() && property_name.as_string() == vm.names.length.as_string()) {
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// a. Return ? ArraySetLength(A, Desc).
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auto success = set_length(property_descriptor);
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if (auto* exception = vm.exception())
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return throw_completion(exception->value());
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return success;
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}
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// 3. Else if P is an array index, then
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if (property_name.is_number()) {
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// a. Let oldLenDesc be OrdinaryGetOwnProperty(A, "length").
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// b. Assert: ! IsDataDescriptor(oldLenDesc) is true.
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// c. Assert: oldLenDesc.[[Configurable]] is false.
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// d. Let oldLen be oldLenDesc.[[Value]].
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// e. Assert: oldLen is a non-negative integral Number.
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// f. Let index be ! ToUint32(P).
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// g. If index ≥ oldLen and oldLenDesc.[[Writable]] is false, return false.
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if (property_name.as_number() >= indexed_properties().array_like_size() && !m_length_writable)
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return false;
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// h. Let succeeded be ! OrdinaryDefineOwnProperty(A, P, Desc).
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auto succeeded = MUST(Object::internal_define_own_property(property_name, property_descriptor));
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// i. If succeeded is false, return false.
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if (!succeeded)
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return false;
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// j. If index ≥ oldLen, then
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// i. Set oldLenDesc.[[Value]] to index + 1𝔽.
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// ii. Set succeeded to OrdinaryDefineOwnProperty(A, "length", oldLenDesc).
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// iii. Assert: succeeded is true.
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// k. Return true.
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return true;
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}
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// 4. Return OrdinaryDefineOwnProperty(A, P, Desc).
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return Object::internal_define_own_property(property_name, property_descriptor);
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}
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// NON-STANDARD: Used to reject deletes to ephemeral (non-configurable) length property
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ThrowCompletionOr<bool> Array::internal_delete(PropertyName const& property_name)
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{
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auto& vm = this->vm();
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if (property_name.is_string() && property_name.as_string() == vm.names.length.as_string())
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return false;
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return Object::internal_delete(property_name);
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}
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// NON-STANDARD: Used to inject the ephemeral length property's key
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ThrowCompletionOr<MarkedValueList> Array::internal_own_property_keys() const
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{
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auto& vm = this->vm();
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auto keys = TRY(Object::internal_own_property_keys());
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// FIXME: This is pretty expensive, find a better way to do this
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keys.insert(indexed_properties().real_size(), js_string(vm, vm.names.length.as_string()));
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return { move(keys) };
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}
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}
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