public:

static const std::string EXTENSIONS[];

static void Initialize(v8::Local<v8::Object> target,

v8::Local<v8::Value> unused,

v8::Local<v8::Context> context);

private:

ModuleWrap(node::Environment* env,

v8::Local<v8::Object> object,

v8::Local<v8::Module> module,

v8::Local<v8::String> url);

~ModuleWrap();

static void New(const v8::FunctionCallbackInfo<v8::Value>& args);

static void Link(const v8::FunctionCallbackInfo<v8::Value>& args);

static void Instantiate(const v8::FunctionCallbackInfo<v8::Value>& args);

static void Evaluate(const v8::FunctionCallbackInfo<v8::Value>& args);

static void GetUrl(v8::Local<v8::String> property,

const v8::PropertyCallbackInfo<v8::Value>& info);

static void Resolve(const v8::FunctionCallbackInfo<v8::Value>& args);

static v8::MaybeLocal<v8::Module> ResolveCallback(

v8::Local<v8::Context> context,

v8::Local<v8::String> specifier,

v8::Local<v8::Module> referrer);

v8::Persistent<v8::Module> module_;

v8::Persistent<v8::String> url_;

bool linked_ = false;

std::unordered_map<std::string, v8::Persistent<v8::Promise>> resolve_cache_;