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LibJS: Implement String.prototype.charCodeAt with UTF-16 code units

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Timothy Flynn 2021-07-19 11:15:18 -04:00 • committed by Andreas Kling
parent 5d11614bc7
commit 48a28a9a73
2 changed files with 15 additions and 4 deletions
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11
Userland/Libraries/LibJS/Runtime/StringPrototype.cpp
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@ -145,15 +145,18 @@ JS_DEFINE_NATIVE_FUNCTION(StringPrototype::char_at)
// 22.1.3.2 String.prototype.charCodeAt ( pos ), https://tc39.es/ecma262/#sec-string.prototype.charcodeat
JS_DEFINE_NATIVE_FUNCTION(StringPrototype::char_code_at)
{
auto string = ak_string_from(vm, global_object);
if (!string.has_value())
auto string = utf16_string_from(vm, global_object);
if (vm.exception())
return {};
auto position = vm.argument(0).to_integer_or_infinity(global_object);
if (vm.exception())
return {};
if (position < 0 || position >= string->length())
Utf16View utf16_string_view { string };
if (position < 0 || position >= utf16_string_view.length_in_code_units())
return js_nan();
return Value((*string)[position]);
return Value(utf16_string_view.code_unit_at(position));
}
// 22.1.3.3 String.prototype.codePointAt ( pos ), https://tc39.es/ecma262/#sec-string.prototype.codepointat

8
Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.charCodeAt.js
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@ -19,3 +19,11 @@ test("basic functionality", () => {
expect(s.charCodeAt("foo")).toBe(70);
expect(s.charCodeAt(undefined)).toBe(70);
});
test("UTF-16", () => {
var s = "😀";
expect(s).toHaveLength(2);
expect(s.charCodeAt(0)).toBe(0xd83d);
expect(s.charCodeAt(1)).toBe(0xde00);
expect(s.charCodeAt(2)).toBe(NaN);
});