native.cc

#include <node.h>

const int maxValue = 10;
int numberOfCalls = 0;

void WhoAmI(const v8::FunctionCallbackInfo<v8::Value> &args)
{
    v8::Isolate *isolate = args.GetIsolate();
    auto message = v8::String::NewFromUtf8(isolate, "I'm a Node Hero!");
    args.GetReturnValue().Set(message);
}

void Increment(const v8::FunctionCallbackInfo<v8::Value> &args)
{
    v8::Isolate *isolate = args.GetIsolate();

    if (!args[0]->IsNumber())
    {
        isolate->ThrowException(v8::Exception::TypeError(
            v8::String::NewFromUtf8(isolate, "Argument must be a number")));
        return;
    }

    double argsValue = args[0]->NumberValue();
    if (numberOfCalls + argsValue > maxValue)
    {
        isolate->ThrowException(v8::Exception::Error(
            v8::String::NewFromUtf8(isolate, "Counter went through the roof!")));
        return;
    }

    numberOfCalls += argsValue;

    auto currentNumberOfCalls =
        v8::Number::New(isolate, static_cast<double>(numberOfCalls));

    args.GetReturnValue().Set(currentNumberOfCalls);
}

void Initialize(v8::Local<v8::Object> exports)
{
    NODE_SET_METHOD(exports, "whoami", WhoAmI);
    NODE_SET_METHOD(exports, "increment", Increment);
}

NODE_MODULE(module_name, Initialize)