Pass CPP object to JavaScript function

main.cc

/**
 * Pass CPP object to JavaScript function
 * 
 * sample.js:
 * function fileInfo(obj)
 * {
 *  return "fileInfo: " + obj.i;
 * }
 * 
 * To compile: g++ main.cc -o main `pkg-config --cflags --libs javascriptcoregtk-4.0`
 *
 */

#include <iostream>
#include <string>
#include <fstream>
#include <streambuf>

#include <jsc/jsc.h>

using namespace std;

class Sample {
public:
    Sample(int i) { this->i = i; };
    JSCValue* toJSObject(JSCContext* jsContext);
    int i;
};

JSCValue* Sample::toJSObject(JSCContext* jsContext)
{
    JSCValue* ret = jsc_value_new_object(jsContext, nullptr, nullptr); 

    JSCValue* i = jsc_value_new_number(jsContext, this->i);
    jsc_value_object_define_property_data(ret, "i", JSC_VALUE_PROPERTY_ENUMERABLE, i);

    return ret;
}

int main(int argc, char* argv[])
{
    // Create jsContext.
    JSCContext* jsContext = jsc_context_new();

    // Load JavaScript file.
    const std::string filename = {"sample.js"};
    ifstream t("sample.js");
    string code((std::istreambuf_iterator<char>(t)),
            std::istreambuf_iterator<char>());
    JSCValue* ret = jsc_context_evaluate(jsContext, code.c_str(), static_cast<gssize>(code.length()));

    // Query 'fileInfo' and store it into JSCValue.
    JSCValue* fileInfo = jsc_context_evaluate(jsContext, "fileInfo", 8);
    if (!jsc_value_is_function(fileInfo)) {
        cerr << "Couldn't find function 'fileInfo'" << endl;
        exit(EXIT_FAILURE);
    }

    // Create CPP object.
    Sample obj(42);

    // Convert to JSCValue object and call 'fileInfo' function.
    ret = jsc_value_function_call(fileInfo, JSC_TYPE_VALUE, obj.toJSObject(jsContext), G_TYPE_NONE);
    cout << "ret: [" << jsc_value_to_string(ret) << "]" << endl;

    return 0;
}