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LibJS: Support mapFn argument of Array.from

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This commit is contained in:
tuqqu 2021-04-06 23:12:38 +03:00 • committed by Andreas Kling
parent bb9cd13a56
commit 7bd0384fa6
2 changed files with 115 additions and 33 deletions
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41
Userland/Libraries/LibJS/Runtime/ArrayConstructor.cpp
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@ -95,15 +95,37 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from)
auto* array = Array::create(global_object);
Function* map_fn = nullptr;
if (!vm.argument(1).is_undefined()) {
auto callback = vm.argument(1);
if (!callback.is_function()) {
vm.throw_exception<TypeError>(global_object, ErrorType::NotAFunction, callback.to_string_without_side_effects());
return {};
}
map_fn = &callback.as_function();
}
// Array.from() lets you create Arrays from:
if (auto size = object->indexed_properties().array_like_size()) {
// * array-like objects (objects with a length property and indexed elements)
MarkedValueList elements(vm.heap());
elements.ensure_capacity(size);
for (size_t i = 0; i < size; ++i) {
elements.append(object->get(i));
if (vm.exception())
return {};
if (map_fn) {
auto element = object->get(i);
if (vm.exception())
return {};
auto map_fn_result = vm.call(*map_fn, value, element);
if (vm.exception())
return {};
elements.append(map_fn_result);
} else {
elements.append(object->get(i));
if (vm.exception())
return {};
}
}
array->set_indexed_property_elements(move(elements));
} else {
@ -111,14 +133,23 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from)
get_iterator_values(global_object, value, [&](Value element) {
if (vm.exception())
return IterationDecision::Break;
array->indexed_properties().append(element);
if (map_fn) {
auto map_fn_result = vm.call(*map_fn, value, element);
if (vm.exception())
return IterationDecision::Break;
array->indexed_properties().append(map_fn_result);
} else {
array->indexed_properties().append(element);
}
return IterationDecision::Continue;
});
if (vm.exception())
return {};
}
// FIXME: if interpreter.argument_count() >= 2: mapFn
// FIXME: if interpreter.argument_count() >= 3: thisArg
return array;