LibJS: Implement Set.prototype.difference

This commit is contained in:
Idan Horowitz 2022-12-01 22:33:26 +02:00 committed by Linus Groh
parent 9e693304ff
commit be8329d5f6
Notes: sideshowbarker 2024-07-17 05:13:53 +09:00
4 changed files with 84 additions and 0 deletions

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@ -148,6 +148,7 @@ namespace JS {
P(deleteProperty) \
P(deref) \
P(description) \
P(difference) \
P(direction) \
P(disambiguation) \
P(done) \

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@ -34,6 +34,7 @@ void SetPrototype::initialize(Realm& realm)
define_native_function(realm, vm.names.values, values, 0, attr);
define_native_function(realm, vm.names.union_, union_, 1, attr);
define_native_function(realm, vm.names.intersection, intersection, 1, attr);
define_native_function(realm, vm.names.difference, difference, 1, attr);
define_native_accessor(realm, vm.names.size, size_getter, {}, Attribute::Configurable);
define_direct_property(vm.names.keys, get_without_side_effects(vm.names.values), attr);
@ -313,4 +314,73 @@ JS_DEFINE_NATIVE_FUNCTION(SetPrototype::intersection)
return result;
}
// 3 Set.prototype.difference ( other ), https://tc39.es/proposal-set-methods/#sec-set.prototype.difference
JS_DEFINE_NATIVE_FUNCTION(SetPrototype::difference)
{
// 1. Let O be the this value.
// 2. Perform ? RequireInternalSlot(O, [[SetData]]).
auto* set = TRY(typed_this_object(vm));
// 3. Let otherRec be ? GetSetRecord(other).
auto other_record = TRY(get_set_record(vm, vm.argument(0)));
// 4. Let resultSetData be a copy of O.[[SetData]].
auto result = set->copy();
// 5. Let thisSize be the number of elements in O.[[SetData]].
auto this_size = set->set_size();
// 6. If thisSize ≤ otherRec.[[Size]], then
if (this_size <= other_record.size) {
// a. For each element e of resultSetData, do
for (auto& element : *set) {
// i. If e is not empty, then
// 1. Let inOther be ToBoolean(? Call(otherRec.[[Has]], otherRec.[[Set]], « e »)).
auto in_other = TRY(call(vm, *other_record.has, other_record.set, element.key)).to_boolean();
// 2. If inOther is true, then
if (in_other) {
// a. Remove e from resultSetData.
result->set_remove(element.key);
}
}
}
// 7. Else,
else {
// a. Let keysIter be ? GetKeysIterator(otherRec).
auto keys_iterator = TRY(get_keys_iterator(vm, other_record));
// b. Let next be true.
auto next = true;
// c. Repeat, while next is not false,
while (next) {
// i. Set next to ? IteratorStep(keysIter).
auto* iterator_result = TRY(iterator_step(vm, keys_iterator));
next = iterator_result;
// ii. If next is not false, then
if (next) {
// 1. Let nextValue be ? IteratorValue(next).
auto next_value = TRY(iterator_value(vm, *iterator_result));
// 2. If nextValue is -0𝔽, set nextValue to +0𝔽.
if (next_value.is_negative_zero())
next_value = Value(0);
// 3. If SetDataHas(resultSetData, nextValue) is true, then
if (result->set_has(next_value)) {
// a. Remove nextValue from resultSetData.
result->set_remove(next_value);
}
}
}
}
// 8. Let result be OrdinaryObjectCreate(%Set.prototype%, « [[SetData]] »).
// 9. Set result.[[SetData]] to resultSetData.
// 10. Return result.
return result;
}
}

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@ -30,6 +30,7 @@ private:
JS_DECLARE_NATIVE_FUNCTION(values);
JS_DECLARE_NATIVE_FUNCTION(union_);
JS_DECLARE_NATIVE_FUNCTION(intersection);
JS_DECLARE_NATIVE_FUNCTION(difference);
JS_DECLARE_NATIVE_FUNCTION(size_getter);
};

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@ -0,0 +1,12 @@
test("basic functionality", () => {
expect(Set.prototype.difference).toHaveLength(1);
const set1 = new Set(["a", "b", "c"]);
const set2 = new Set(["b", "c", "d", "e"]);
const difference1to2 = set1.difference(set2);
expect(difference1to2).toHaveSize(1);
expect(difference1to2.has("a")).toBeTrue();
const difference2to1 = set2.difference(set1);
expect(difference2to1).toHaveSize(2);
["d", "e"].forEach(value => expect(difference2to1.has(value)).toBeTrue());
});