strict_type_demo.cpp

#include <node.h>
#include <string>
#include <algorithm>
#include <iostream>

using namespace v8;

/* Demonstrates converstions of v8:Value's passed as arguments.
   See https://v8docs.nodesource.com/node-0.8/dc/d0a/classv8_1_1_value.html
   for more types and conversion methods
*/
Local<Value> make_return(Isolate * isolate, const Local<Object> input ) ;


/* NOTE:  Anytime you fail to set the return value - args.getReturnValue().Set(...) -
          your addon will return undefined
*/

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

    if ( args.Length() < 1 ) {
        return;
    }

    if ( !args[0]->IsNumber()) {
        return;
    }

    double value = args[0]->NumberValue();

    Local<Number> retval = Number::New(isolate, value + 42);
    args.GetReturnValue().Set(retval);
}

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

    if ( args.Length() < 1 ) {
        return;
    }

    if ( !args[0]->IsInt32()) {
        return;
    }

    int value = args[0]->Int32Value();

    Local<Number> retval = Int32::New(isolate, value + 42);
    args.GetReturnValue().Set(retval);
}

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

    if ( args.Length() < 1 || !args[0]->IsBoolean()) {
        return;
    }

    bool value = args[0]->BooleanValue();

    Local<Boolean> retval = Boolean::New(isolate, !value);
    args.GetReturnValue().Set(retval);
}

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

    if ( args.Length() < 1 ) {
        return;
    }
    else if ( args[0]->IsNull() ) {
        return;
    }
    else if ( args[0]->IsUndefined() ) {
        return;
    }
    else if (!args[0]->IsString()) {
        // This clause would catch IsNull and IsUndefined too...
        return ;
    }

    v8::String::Utf8Value s(args[0]);
    std::string str(*s, s.length());
    std::reverse(str.begin(), str.end());

    Local<String> retval = String::NewFromUtf8(isolate, str.c_str());
    args.GetReturnValue().Set(retval);
}

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

    if ( args.Length() < 1 || ! args[0]->IsObject()) {
        // just return undefined
        return;
    }

    Local<Object> target = args[0]->ToObject();

    Local<Value> obj = make_return(isolate, target);

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

void PassArray(const FunctionCallbackInfo<Value>& args) {
    Isolate * isolate = args.GetIsolate();
    Local<Array> array = Local<Array>::Cast(args[0]);

    if ( args.Length() < 1 || ! args[0]->IsArray()) {
        return;
    }

    if (array->Length() < 3) {
        return;
    }

    Local<String> prop = String::NewFromUtf8(isolate, "not_index");
    if (array->Get(prop)->IsUndefined() ){
        return;
    }

    for (unsigned int i = 0; i < 3; i++ ) {
      if (array->Has(i)) {
        Local<Value> v = array->Get(i);
        if ( !v->IsNumber()) return;

        double value = v->NumberValue();
        array->Set(i, Number::New(isolate, value + 1));
      }
      else {
        return;
      }
    }

    Local<Array> a = Array::New(isolate);
    a->Set(0, array->Get(0));
    a->Set(1, array->Get(prop));
    a->Set(2, array->Get(2));

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



Local<Value> make_return(Isolate * isolate, const Local<Object> input ) {
    Local<String> x_prop = String::NewFromUtf8(isolate, "x");
    Local<String> y_prop = String::NewFromUtf8(isolate, "y");
    Local<String> sum_prop = String::NewFromUtf8(isolate, "sum");
    Local<String> product_prop = String::NewFromUtf8(isolate, "product");

    Local<Value> x_value = input->Get(x_prop);
    Local<Value> y_value = input->Get(y_prop);

    if ( !x_value->IsNumber() || !y_value->IsNumber()) {
        return v8::Undefined(isolate);
    }


    double x = input->Get(x_prop)->NumberValue();
    double y = input->Get(y_prop)->NumberValue();

    Local<Object> obj = Object::New(isolate);
    obj->Set(sum_prop, Number::New(isolate, x + y));
    obj->Set(product_prop, Number::New(isolate, x * y));
    return obj;
}




void init(Local<Object> exports) {
  NODE_SET_METHOD(exports, "pass_number", PassNumber);
  NODE_SET_METHOD(exports, "pass_integer", PassInteger);
  NODE_SET_METHOD(exports, "pass_string", PassString);
  NODE_SET_METHOD(exports, "pass_boolean", PassBoolean);
  NODE_SET_METHOD(exports, "pass_object", PassObject);
  NODE_SET_METHOD(exports, "pass_array", PassArray);
}

NODE_MODULE(strict_type_demo, init)