feat: javascript helpers extension

fix #881

Author: alandefreitas

src/lib/Support/JavaScript.cpp

@@ -840,14 +840,8 @@ static jerry_value_t toJsValue(dom::Value const& v, std::shared_ptr<Context::Imp
     case dom::Kind::Boolean: return jerry_boolean(v.getBool());
     case dom::Kind::Integer:
     {
-        // JerryScript stores small integers in a compact tagged form; passing
-        // values outside the host `int` range trips UBSan during the internal
-        // cast. Clamp to the supported range to avoid UB under sanitizers.
+        // Preserve the full 53-bit integer precision JavaScript numbers support.
         auto i = v.getInteger();
-        if (i > std::numeric_limits<int>::max())
-            return jerry_number(static_cast<double>(std::numeric_limits<int>::max()));
-        if (i < std::numeric_limits<int>::min())
-            return jerry_number(static_cast<double>(std::numeric_limits<int>::min()));
         return jerry_number(static_cast<double>(i));
     }
     case dom::Kind::String:

src/test/Support/JavaScript.cpp

@@ -220,6 +220,18 @@ struct JavaScript_test
             BOOST_TEST(y.getDom() == 1);
         }
 
+        // setGlobal with 64-bit integers preserves the full value
+        {
+            Scope scope(ctx);
+            auto const big = static_cast<std::int64_t>(1) << 33;
+            scope.setGlobal("big", dom::Value(big));
+            auto exp = scope.getGlobal("big");
+            BOOST_TEST(exp);
+            js::Value bigVal = *exp;
+            BOOST_TEST(bigVal.isNumber());
+            BOOST_TEST(bigVal.getDom() == big);
+        }
+
         // getGlobalObject
         {
             Scope scope(ctx);