LibJS: Add String.prototype.split using the @@split methods on object

Userland/Libraries/LibJS/Runtime/StringPrototype.cpp

@@ -575,58 +575,69 @@ JS_DEFINE_NATIVE_FUNCTION(StringPrototype::slice)
 // 22.1.3.21 String.prototype.split ( separator, limit ), https://tc39.es/ecma262/#sec-string.prototype.split
 JS_DEFINE_NATIVE_FUNCTION(StringPrototype::split)
 {
- // FIXME Implement the @@split part
+ auto separator_argument = vm.argument(0);
+ auto limit_argument = vm.argument(1);
 
- auto string = ak_string_from(vm, global_object);
- if (!string.has_value())
+ auto this_value = require_object_coercible(global_object, vm.this_value(global_object));
+ if (vm.exception())
  return {};
 
+ if (!separator_argument.is_nullish()) {
+ auto splitter = separator_argument.get_method(global_object, *vm.well_known_symbol_split());
+ if (vm.exception())
+ return {};
+ if (splitter)
+ return vm.call(*splitter, separator_argument, this_value, limit_argument);
+ }
+
+ auto string = this_value.to_string(global_object);
+
  auto* result = Array::create(global_object);
  size_t result_len = 0;
 
  auto limit = NumericLimits<u32>::max();
  if (!vm.argument(1).is_undefined()) {
- limit = vm.argument(1).to_u32(global_object);
+ limit = limit_argument.to_u32(global_object);
  if (vm.exception())
  return {};
  }
 
- auto separator = vm.argument(0).to_string(global_object);
+ auto separator = separator_argument.to_string(global_object);
  if (vm.exception())
  return {};
 
  if (limit == 0)
  return result;
 
  if (vm.argument(0).is_undefined()) {
- result->define_property(0, js_string(vm, *string));
+ result->define_property(0, js_string(vm, string));
  return result;
  }
 
- auto len = string->length();
+ auto len = string.length();
  auto separator_len = separator.length();
  if (len == 0) {
  if (separator_len > 0)
- result->define_property(0, js_string(vm, *string));
+ result->define_property(0, js_string(vm, string));
  return result;
  }
 
  size_t start = 0;
  auto pos = start;
  if (separator_len == 0) {
  for (pos = 0; pos < len; pos++)
- result->define_property(pos, js_string(vm, string->substring(pos, 1)));
+ result->define_property(pos, js_string(vm, string.substring(pos, 1)));
  return result;
  }
 
  while (pos != len) {
- auto e = split_match(*string, pos, separator);
+ auto e = split_match(string, pos, separator);
  if (!e.has_value()) {
  pos += 1;
  continue;
  }
 
- auto segment = string->substring_view(start, pos - start);
+ auto segment = string.substring_view(start, pos - start);
  result->define_property(result_len, js_string(vm, segment));
  result_len++;
  if (result_len == limit)
@@ -635,7 +646,7 @@ JS_DEFINE_NATIVE_FUNCTION(StringPrototype::split)
  pos = start;
  }
 
- auto rest = string->substring(start, len - start);
+ auto rest = string.substring(start, len - start);
  result->define_property(result_len, js_string(vm, rest));
 
  return result;