NAN contains functions that convert v8::Values to other v8::Value types and native types. Since type conversion is not guaranteed to succeed, they return Nan::Maybe types. These converters can be used in place of value->ToX() and value->XValue() (where X is one of the types, e.g. Boolean) in a way that provides a consistent interface across V8 versions. Newer versions of V8 use the new v8::Maybe and v8::MaybeLocal types for these conversions, older versions don’t have this functionality so it is provided by NAN.


Converts a v8::Local<v8::Value> to a different subtype of v8::Value or to a native data type. Returns a Nan::MaybeLocal<> or a Nan::Maybe<> accordingly.

See for more information on Nan::Maybe types.


// V8 types
Nan::MaybeLocal<v8::Boolean> Nan::To<v8::Boolean>(v8::Local<v8::Value> val);
Nan::MaybeLocal<v8::Int32> Nan::To<v8::Int32>(v8::Local<v8::Value> val);
Nan::MaybeLocal<v8::Integer> Nan::To<v8::Integer>(v8::Local<v8::Value> val);
Nan::MaybeLocal<v8::Object> Nan::To<v8::Object>(v8::Local<v8::Value> val);
Nan::MaybeLocal<v8::Number> Nan::To<v8::Number>(v8::Local<v8::Value> val);
Nan::MaybeLocal<v8::String> Nan::To<v8::String>(v8::Local<v8::Value> val);
Nan::MaybeLocal<v8::Uint32> Nan::To<v8::Uint32>(v8::Local<v8::Value> val);

// Native types
Nan::Maybe<bool> Nan::To<bool>(v8::Local<v8::Value> val);
Nan::Maybe<double> Nan::To<double>(v8::Local<v8::Value> val);
Nan::Maybe<int32_t> Nan::To<int32_t>(v8::Local<v8::Value> val);
Nan::Maybe<int64_t> Nan::To<int64_t>(v8::Local<v8::Value> val);
Nan::Maybe<uint32_t> Nan::To<uint32_t>(v8::Local<v8::Value> val);


v8::Local<v8::Value> val;
Nan::MaybeLocal<v8::String> str = Nan::To<v8::String>(val);
Nan::Maybe<double> d = Nan::To<double>(val);