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LibJS: Implement initializing a TypedArray from an array-like object

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Used by twitch.tv and based on the following specification:
https://tc39.es/ecma262/#sec-initializetypedarrayfromarraylike
This commit is contained in:
Idan Horowitz 2021-04-16 23:24:59 +03:00 • committed by Linus Groh
parent c9196995be
commit 06a2173586
2 changed files with 54 additions and 2 deletions
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44
Userland/Libraries/LibJS/Runtime/TypedArray.cpp
View file

@ -135,6 +135,37 @@ static void initialize_typed_array_from_typed_array(GlobalObject& global_object,
dest_array.put_by_index(i, v);
}
}
template<typename T>
static void initialize_typed_array_from_array_like(GlobalObject& global_object, TypedArray<T>& typed_array, const Object& array_like)
{
// 23.2.5.1.5 InitializeTypedArrayFromArrayLike, https://tc39.es/ecma262/#sec-initializetypedarrayfromarraylike
auto& vm = global_object.vm();
auto length = length_of_array_like(global_object, array_like);
if (vm.exception())
return;
auto element_size = typed_array.element_size();
if (Checked<size_t>::multiplication_would_overflow(element_size, length)) {
vm.throw_exception<RangeError>(global_object, ErrorType::InvalidLength, "typed array");
return;
}
auto byte_length = element_size * length;
auto array_buffer = ArrayBuffer::create(global_object, byte_length);
typed_array.set_viewed_array_buffer(array_buffer);
typed_array.set_byte_length(byte_length);
typed_array.set_byte_offset(0);
typed_array.set_array_length(length);
for (size_t k = 0; k < length; k++) {
auto value = array_like.get(k).value_or(js_undefined());
if (vm.exception())
return;
typed_array.put_by_index(k, value);
if (vm.exception())
return;
}
}
void TypedArrayBase::visit_edges(Visitor& visitor)
{
@ -199,8 +230,17 @@ void TypedArrayBase::visit_edges(Visitor& visitor)
if (vm.exception()) \
return {}; \
} else { \
/* FIXME: Initialize from Iterator or Array-like object */ \
TODO(); \
auto iterator = first_argument.as_object().get(vm.well_known_symbol_iterator()); \
if (vm.exception()) \
return {}; \
if (iterator.is_function()) { \
/* FIXME: Initialize from Iterator */ \
TODO(); \
} else { \
initialize_typed_array_from_array_like(global_object(), *typed_array, first_argument.as_object()); \
} \
if (vm.exception()) \
return {}; \
} \
return typed_array; \
} \

12
Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.js
View file

@ -183,6 +183,18 @@ test("typed array created from TypedArray do not share buffer", () => {
expect(u8Array[1]).toBe(2);
});
test("typed array from Array-Like", () => {
TYPED_ARRAYS.forEach(T => {
function func() {
const newTypedArray = new T(arguments);
expect(newTypedArray[0]).toBe(1);
expect(newTypedArray[1]).toBe(2);
expect(newTypedArray[2]).toBe(3);
}
func(1, 2, 3);
});
});
test("TypedArray is not exposed on the global object", () => {
expect(globalThis.TypedArray).toBeUndefined();
});