diff --git a/src/builtins/BuiltinRegExp.cpp b/src/builtins/BuiltinRegExp.cpp
index 623c737b2..a048edd0b 100644
--- a/src/builtins/BuiltinRegExp.cpp
+++ b/src/builtins/BuiltinRegExp.cpp
@@ -679,6 +679,11 @@ static Value builtinRegExpUnicodeGetter(ExecutionState& state, Value thisValue,
     return builtinRegExpOptionGetterHelper(state, thisValue, RegExpObject::Option::Unicode);
 }
 
+static Value builtinRegExpUnicodeSetsGetter(ExecutionState& state, Value thisValue, size_t argc, Value* argv, Optional<Object*> newTarget)
+{
+    return builtinRegExpOptionGetterHelper(state, thisValue, RegExpObject::Option::UnicodeSets);
+}
+
 
 // Legacy RegExp Features (non-standard)
 static Value builtinRegExpInputGetter(ExecutionState& state, Value thisValue, size_t argc, Value* argv, Optional<Object*> newTarget)
@@ -928,6 +933,13 @@ void GlobalObject::installRegExp(ExecutionState& state)
         m_regexpPrototype->directDefineOwnProperty(state, ObjectPropertyName(state, strings->unicode), desc);
     }
 
+    {
+        Value getter = new NativeFunctionObject(state, NativeFunctionInfo(strings->getUnicodeSets, builtinRegExpUnicodeSetsGetter, 0, NativeFunctionInfo::Strict));
+        JSGetterSetter gs(getter, Value());
+        ObjectPropertyDescriptor desc(gs, ObjectPropertyDescriptor::ConfigurablePresent);
+        m_regexpPrototype->directDefineOwnProperty(state, ObjectPropertyName(state, strings->unicodeSets), desc);
+    }
+
     m_regexpPrototype->directDefineOwnProperty(state, ObjectPropertyName(strings->constructor), ObjectPropertyDescriptor(m_regexp, (ObjectPropertyDescriptor::PresentAttribute)(ObjectPropertyDescriptor::WritablePresent | ObjectPropertyDescriptor::ConfigurablePresent)));
 
     m_regexp->setFunctionPrototype(state, m_regexpPrototype);
diff --git a/src/runtime/RegExpObject.cpp b/src/runtime/RegExpObject.cpp
index b8fc3fa9b..4b1ad6c53 100644
--- a/src/runtime/RegExpObject.cpp
+++ b/src/runtime/RegExpObject.cpp
@@ -223,6 +223,8 @@ RegExpObject::Option RegExpObject::parseOption(ExecutionState& state, String* op
         case 'u':
             if (tempOption & Option::Unicode)
                 ErrorObject::throwBuiltinError(state, ErrorCode::SyntaxError, "RegExp has multiple 'u' flags");
+            if (tempOption & Option::UnicodeSets)
+                ErrorObject::throwBuiltinError(state, ErrorCode::SyntaxError, "RegExp already have 'v' flag");
             tempOption = (Option)(tempOption | Option::Unicode);
             break;
         case 'y':
@@ -238,6 +240,8 @@ RegExpObject::Option RegExpObject::parseOption(ExecutionState& state, String* op
         case 'v':
             if (tempOption & Option::UnicodeSets)
                 ErrorObject::throwBuiltinError(state, ErrorCode::SyntaxError, "RegExp has multiple 'v' flags");
+            if (tempOption & Option::Unicode)
+                ErrorObject::throwBuiltinError(state, ErrorCode::SyntaxError, "RegExp already have 'u' flag");
             tempOption = (Option)(tempOption | Option::UnicodeSets);
             break;
         case 'd':
diff --git a/src/runtime/StaticStrings.cpp b/src/runtime/StaticStrings.cpp
index e82666ec0..f22df35f4 100644
--- a/src/runtime/StaticStrings.cpp
+++ b/src/runtime/StaticStrings.cpp
@@ -117,6 +117,7 @@ void StaticStrings::initStaticStrings()
     INIT_STATIC_STRING(getTextInfo, "get textInfo");
     INIT_STATIC_STRING(getTimeZones, "get timeZones");
     INIT_STATIC_STRING(getUnicode, "get unicode");
+    INIT_STATIC_STRING(getUnicodeSets, "get unicodeSets");
     INIT_STATIC_STRING(getWeekInfo, "get weekInfo");
     INIT_STATIC_STRING(get__proto__, "get __proto__");
     INIT_STATIC_STRING(getbyteLength, "get byteLength");
diff --git a/src/runtime/StaticStrings.h b/src/runtime/StaticStrings.h
index d231e560a..2408ed927 100644
--- a/src/runtime/StaticStrings.h
+++ b/src/runtime/StaticStrings.h
@@ -1023,6 +1023,7 @@ class StaticStrings {
     AtomicString getTextInfo;
     AtomicString getTimeZones;
     AtomicString getUnicode;
+    AtomicString getUnicodeSets;
     AtomicString getWeekInfo;
     AtomicString get__proto__;
     AtomicString getbyteLength;