d9d245faa7
Iterator.from creates an Iterator from either an existing iterator or an iterator-like object. In the latter case, it sets the prototype of the returned iterator to WrapForValidIteratorPrototype to wrap around the iterator-like object's iteration methods.
72 lines
2.2 KiB
C++
72 lines
2.2 KiB
C++
/*
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* Copyright (c) 2023, Tim Flynn <trflynn89@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 <LibJS/Runtime/AbstractOperations.h>
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#include <LibJS/Runtime/Iterator.h>
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#include <LibJS/Runtime/VM.h>
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namespace JS {
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ThrowCompletionOr<NonnullGCPtr<Iterator>> Iterator::create(Realm& realm, Object& prototype, IteratorRecord iterated)
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{
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return MUST_OR_THROW_OOM(realm.heap().allocate<Iterator>(realm, prototype, move(iterated)));
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}
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Iterator::Iterator(Object& prototype, IteratorRecord iterated)
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: Object(ConstructWithPrototypeTag::Tag, prototype)
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, m_iterated(move(iterated))
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{
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}
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Iterator::Iterator(Object& prototype)
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: Iterator(prototype, {})
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{
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}
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// 2.1.1 GetIteratorDirect ( obj ), https://tc39.es/proposal-iterator-helpers/#sec-getiteratorflattenable
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ThrowCompletionOr<IteratorRecord> get_iterator_direct(VM& vm, Object& object)
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{
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// 1. Let nextMethod be ? Get(obj, "next").
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auto next_method = TRY(object.get(vm.names.next));
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// 2. Let iteratorRecord be Record { [[Iterator]]: obj, [[NextMethod]]: nextMethod, [[Done]]: false }.
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IteratorRecord iterator_record { .iterator = object, .next_method = next_method, .done = false };
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// 3. Return iteratorRecord.
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return iterator_record;
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}
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ThrowCompletionOr<IteratorRecord> get_iterator_flattenable(VM& vm, Value object)
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{
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// 1. If obj is not an Object, throw a TypeError exception.
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if (!object.is_object())
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return vm.throw_completion<TypeError>(ErrorType::NotAnObject, "obj"sv);
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// 2. Let method be ? GetMethod(obj, @@iterator).
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auto method = TRY(object.get_method(vm, vm.well_known_symbol_iterator()));
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Value iterator;
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// 3. If method is undefined, then
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if (!method) {
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// a. Let iterator be obj.
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iterator = object;
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}
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// 4. Else,
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else {
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// a. Let iterator be ? Call(method, obj).
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iterator = TRY(call(vm, method, object));
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}
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// 5. If iterator is not an Object, throw a TypeError exception.
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if (!iterator.is_object())
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return vm.throw_completion<TypeError>(ErrorType::NotAnObject, "iterator"sv);
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// 6. Return ? GetIteratorDirect(iterator).
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return TRY(get_iterator_direct(vm, iterator.as_object()));
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}
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}
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