[regexp] Named capture support for string replacements

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index d4185029dec568d67468947cd1e90ffd5bc3a297..7b9923d1bcd29cd5a1cfdd68901fd6e0d763260e 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11403,6 +11403,8 @@ int String::IndexOf(Isolate* isolate, Handle<String> receiver,
 
 MaybeHandle<String> String::GetSubstitution(Isolate* isolate, Match* match,
                                             Handle<String> replacement) {
+  DCHECK_IMPLIES(match->HasNamedCaptures(), FLAG_harmony_regexp_named_captures);
+
   Factory* factory = isolate->factory();
 
   const int replacement_length = replacement->length();
@@ -11489,6 +11491,37 @@ MaybeHandle<String> String::GetSubstitution(Isolate* isolate, Match* match,
         continue_from_ix = peek_ix + advance;
         break;
       }
+      case '<': {  // $<name> - named capture
+        if (!match->HasNamedCaptures()) {
+          builder.AppendCharacter('$');
+          continue_from_ix = peek_ix;
+          break;
+        }
+
+        Handle<String> bracket_string =
+            factory->LookupSingleCharacterStringFromCode('>');
+        const int closing_bracket_ix =
+            String::IndexOf(isolate, replacement, bracket_string, peek_ix + 1);
+
+        if (closing_bracket_ix == -1) {
+          THROW_NEW_ERROR(
+              isolate,
+              NewSyntaxError(MessageTemplate::kRegExpInvalidReplaceString,
+                             replacement),
+              String);
+        }
+
+        Handle<String> capture_name =
+            factory->NewSubString(replacement, peek_ix + 1, closing_bracket_ix);
+        bool capture_exists;
+        Handle<String> capture;
+        ASSIGN_RETURN_ON_EXCEPTION(
+            isolate, capture,
+            match->GetNamedCapture(capture_name, &capture_exists), String);
+        if (capture_exists) builder.AppendString(capture);
+        continue_from_ix = closing_bracket_ix + 1;
+        break;
+      }
       default:
         builder.AppendCharacter('$');
         continue_from_ix = peek_ix;
@@ -11659,6 +11692,15 @@ bool String::IsUtf8EqualTo(Vector<const char> str, bool allow_prefix_match) {
   return (allow_prefix_match || i == slen) && remaining_in_str == 0;
 }
 
+template <>
+bool String::IsEqualTo(Vector<const uint8_t> str) {
+  return IsOneByteEqualTo(str);
+}
+
+template <>
+bool String::IsEqualTo(Vector<const uc16> str) {
+  return IsTwoByteEqualTo(str);
+}
 
 bool String::IsOneByteEqualTo(Vector<const uint8_t> str) {
   int slen = length();