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

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Timothy Flynn 2021-07-19 13:34:41 -04:00 • committed by Andreas Kling
parent 60d8852fc2
commit 892bfdbbcf
2 changed files with 18 additions and 10 deletions
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17
Userland/Libraries/LibJS/Runtime/StringPrototype.cpp
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@ -527,14 +527,12 @@ JS_DEFINE_NATIVE_FUNCTION(StringPrototype::substring)
// B.2.3.1 String.prototype.substr ( start, length ), https://tc39.es/ecma262/#sec-string.prototype.substr
JS_DEFINE_NATIVE_FUNCTION(StringPrototype::substr)
{
auto string = ak_string_from(vm, global_object);
if (!string.has_value())
auto string = utf16_string_from(vm, global_object);
if (vm.exception())
return {};
if (vm.argument_count() == 0)
return js_string(vm, *string);
// FIXME: this should index a UTF-16 code_point view of the string.
auto size = (i32)string->length();
Utf16View utf16_string_view { string };
auto size = utf16_string_view.length_in_code_units();
auto int_start = vm.argument(0).to_integer_or_infinity(global_object);
if (vm.exception())
@ -551,15 +549,14 @@ JS_DEFINE_NATIVE_FUNCTION(StringPrototype::substr)
return {};
if (Value(int_start).is_positive_infinity() || (int_length <= 0) || Value(int_length).is_positive_infinity())
return js_string(vm, String(""));
return js_string(vm, String::empty());
auto int_end = min((i32)(int_start + int_length), size);
if (int_start >= int_end)
return js_string(vm, String(""));
return js_string(vm, String::empty());
auto string_part = string->substring(int_start, int_end - int_start);
return js_string(vm, string_part);
return js_string(vm, utf16_string_view.substring_view(int_start, int_end - int_start));
}
// 22.1.3.7 String.prototype.includes ( searchString [ , position ] ), https://tc39.es/ecma262/#sec-string.prototype.includes