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LibJS: Implement %IteratorHelperPrototype%.return

This commit is contained in:
Timothy Flynn 2023-07-16 16:06:06 -04:00 committed by Linus Groh
parent 57e7112a20
commit 0e63d04a35
6 changed files with 263 additions and 6 deletions

View file

@ -44,16 +44,28 @@ JS_DEFINE_NATIVE_FUNCTION(IteratorHelperPrototype::return_)
{
// 1. Let O be this value.
// 2. Perform ? RequireInternalSlot(O, [[UnderlyingIterator]]).
auto iterator = TRY(typed_this_object(vm));
// 3. Assert: O has a [[GeneratorState]] slot.
// 4. If O.[[GeneratorState]] is suspendedStart, then
// a. Set O.[[GeneratorState]] to completed.
// b. NOTE: Once a generator enters the completed state it never leaves it and its associated execution context is never resumed. Any execution state associated with O can be discarded at this point.
// c. Perform ? IteratorClose(O.[[UnderlyingIterator]], NormalCompletion(unused)).
// d. Return CreateIterResultObject(undefined, true).
if (iterator->generator_state() == GeneratorObject::GeneratorState::SuspendedStart) {
// a. Set O.[[GeneratorState]] to completed.
iterator->set_generator_state(GeneratorObject::GeneratorState::Completed);
// b. NOTE: Once a generator enters the completed state it never leaves it and its associated execution context is never resumed. Any execution state associated with O can be discarded at this point.
// c. Perform ? IteratorClose(O.[[UnderlyingIterator]], NormalCompletion(unused)).
TRY(iterator_close(vm, iterator->underlying_iterator(), normal_completion({})));
// d. Return CreateIterResultObject(undefined, true).
return create_iterator_result_object(vm, js_undefined(), true);
}
// 5. Let C be Completion { [[Type]]: return, [[Value]]: undefined, [[Target]]: empty }.
Completion completion { Completion::Type::Return, js_undefined(), {} };
// 6. Return ? GeneratorResumeAbrupt(O, C, "Iterator Helper").
return vm.throw_completion<InternalError>(ErrorType::NotImplemented, "IteratorHelper.prototype.return"sv);
return TRY(iterator->resume_abrupt(vm, move(completion), "Iterator Helper"sv));
}
}

View file

@ -49,6 +49,28 @@ describe("errors", () => {
iterator.next();
}).toThrow(TestError);
});
test("iterator's return method throws", () => {
function TestError() {}
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
throw new TestError();
}
}
expect(() => {
const iterator = new TestIterator().drop(1);
iterator.return();
}).toThrow(TestError);
});
});
describe("normal behavior", () => {
@ -115,4 +137,31 @@ describe("normal behavior", () => {
expect(value.value).toBeUndefined();
expect(value.done).toBeTrue();
});
test("return is forwarded to the underlying iterator's return method", () => {
let returnCount = 0;
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
++returnCount;
return {};
}
}
const iterator = new TestIterator().drop(1);
expect(returnCount).toBe(0);
iterator.return();
expect(returnCount).toBe(1);
iterator.return();
expect(returnCount).toBe(1);
});
});

View file

@ -40,6 +40,28 @@ describe("errors", () => {
}).toThrow(TestError);
});
test("iterator's return method throws", () => {
function TestError() {}
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
throw new TestError();
}
}
expect(() => {
const iterator = new TestIterator().filter(() => true);
iterator.return();
}).toThrow(TestError);
});
test("predicate function throws", () => {
function TestError() {}
@ -153,4 +175,31 @@ describe("normal behavior", () => {
expect(firstFilterCount).toBe(4);
expect(secondFilterCount).toBe(2);
});
test("return is forwarded to the underlying iterator's return method", () => {
let returnCount = 0;
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
++returnCount;
return {};
}
}
const iterator = new TestIterator().filter(() => true);
expect(returnCount).toBe(0);
iterator.return();
expect(returnCount).toBe(1);
iterator.return();
expect(returnCount).toBe(1);
});
});

View file

@ -40,6 +40,28 @@ describe("errors", () => {
}).toThrow(TestError);
});
test("iterator's return method throws", () => {
function TestError() {}
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
throw new TestError();
}
}
expect(() => {
const iterator = new TestIterator().flatMap(() => 0);
iterator.return();
}).toThrow(TestError);
});
test("mapper function throws", () => {
function TestError() {}
@ -138,4 +160,31 @@ describe("normal behavior", () => {
expect(value.value).toBeUndefined();
expect(value.done).toBeTrue();
});
test("return is forwarded to the underlying iterator's return method", () => {
let returnCount = 0;
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
++returnCount;
return {};
}
}
const iterator = new TestIterator().flatMap(() => 0);
expect(returnCount).toBe(0);
iterator.return();
expect(returnCount).toBe(1);
iterator.return();
expect(returnCount).toBe(1);
});
});

View file

@ -40,6 +40,28 @@ describe("errors", () => {
}).toThrow(TestError);
});
test("iterator's return method throws", () => {
function TestError() {}
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
throw new TestError();
}
}
expect(() => {
const iterator = new TestIterator().map(() => 0);
iterator.return();
}).toThrow(TestError);
});
test("mapper function throws", () => {
function TestError() {}
@ -141,4 +163,31 @@ describe("normal behavior", () => {
expect(value.value).toBeUndefined();
expect(value.done).toBeTrue();
});
test("return is forwarded to the underlying iterator's return method", () => {
let returnCount = 0;
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
++returnCount;
return {};
}
}
const iterator = new TestIterator().map(() => 0);
expect(returnCount).toBe(0);
iterator.return();
expect(returnCount).toBe(1);
iterator.return();
expect(returnCount).toBe(1);
});
});

View file

@ -49,6 +49,28 @@ describe("errors", () => {
iterator.next();
}).toThrow(TestError);
});
test("iterator's return method throws", () => {
function TestError() {}
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
throw new TestError();
}
}
expect(() => {
const iterator = new TestIterator().take(1);
iterator.return();
}).toThrow(TestError);
});
});
describe("normal behavior", () => {
@ -120,4 +142,31 @@ describe("normal behavior", () => {
expect(value.value).toBeUndefined();
expect(value.done).toBeTrue();
});
test("return is forwarded to the underlying iterator's return method", () => {
let returnCount = 0;
class TestIterator extends Iterator {
next() {
return {
done: false,
value: 1,
};
}
return() {
++returnCount;
return {};
}
}
const iterator = new TestIterator().take(1);
expect(returnCount).toBe(0);
iterator.return();
expect(returnCount).toBe(1);
iterator.return();
expect(returnCount).toBe(1);
});
});