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

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Timothy Flynn 2021-07-19 12:54:48 -04:00 • committed by Andreas Kling
parent 70f9c7e1c7
commit 767700d8a1
2 changed files with 23 additions and 8 deletions
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23
Userland/Libraries/LibJS/Runtime/StringPrototype.cpp
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@ -338,20 +338,27 @@ JS_DEFINE_NATIVE_FUNCTION(StringPrototype::ends_with)
// 22.1.3.8 String.prototype.indexOf ( searchString [ , position ] ), https://tc39.es/ecma262/#sec-string.prototype.indexof
JS_DEFINE_NATIVE_FUNCTION(StringPrototype::index_of)
{
auto string = ak_string_from(vm, global_object);
if (!string.has_value())
return {};
auto needle = vm.argument(0).to_string(global_object);
auto string = utf16_string_from(vm, global_object);
if (vm.exception())
return {};
size_t from = 0;
auto search_string = vm.argument(0).to_utf16_string(global_object);
if (vm.exception())
return {};
Utf16View utf16_string_view { string };
Utf16View utf16_search_view { search_string };
size_t start = 0;
if (vm.argument_count() > 1) {
double from_argument = vm.argument(1).to_integer_or_infinity(global_object);
auto position = vm.argument(1).to_integer_or_infinity(global_object);
if (vm.exception())
return {};
from = clamp(from_argument, static_cast<double>(0), static_cast<double>(string->length()));
start = clamp(position, static_cast<double>(0), static_cast<double>(utf16_string_view.length_in_code_units()));
}
return Value((i32)string->find(needle, from).value_or(-1));
auto index = string_index_of(utf16_string_view, utf16_search_view, start);
return index.has_value() ? Value(*index) : Value(-1);
}
// 22.1.3.26 String.prototype.toLowerCase ( ), https://tc39.es/ecma262/#sec-string.prototype.tolowercase

8
Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.indexOf.js
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@ -21,3 +21,11 @@ test("basic functionality", () => {
expect(s.indexOf("e", 0)).toBe(1);
expect(s.indexOf("e", 2)).toBe(9);
});
test("UTF-16", () => {
var s = "😀";
expect(s.indexOf("😀")).toBe(0);
expect(s.indexOf("\ud83d")).toBe(0);
expect(s.indexOf("\ude00")).toBe(1);
expect(s.indexOf("a")).toBe(-1);
});