Conversion between v8::value to date

Question

I am writing C++ addon on v8 using nan. One of the arguments to constructor is of Date type. IsDate returns true, but I don't know how to convert it to C++ Date object to get Year, Month and Day and etc..

void NodeObject::New(const Nan::FunctionCallbackInfo<v8::Value>& info) {
    if(info[0]->IsDate()) {
        //convert and get year, month and day
        boost::gregorian::date d(2016 , 1 ,1);
        double price = getPrice(date);
    }
}

Thanks for your helping!

What have you written that attempted to do that conversion? Please provide some code in place of your comment. How is this code not working as expected? — Conspicuous Compiler, Apr 20 '16 at 22:01
@ConspicuousCompiler I've added an example. Basically, I need to call a function that takes boost date. — user2391685, Apr 20 '16 at 22:19

Ross Meikleham · Accepted Answer · 2016-04-20T23:13:13.300

You can cast a v8 Value to a Date object with the v8::Date::Cast function.

From there you can extract the number of milliseconds since the Unix epoch (1st January 1970) with the NumberValue function.

Then convert this number to a std::time_t object by casting the number of seconds static_cast<time_t>(millisSinceEpoch/1000)

From the time_t get a struct *tm with the localtime function.

Then finally extracting the day/month/year values:

void NodeObject::New(const Nan::FunctionCallbackInfo<v8::Value>& info) {
  if(info[0]->IsDate()) {
    double millisSinceEpoch = v8::Date::Cast(*info[0])->NumberValue(); 
    std::time_t t = static_cast<time_t>(millisSinceEpoch/1000);

    struct tm* ltime = localtime(&t);
    int year = ltime->tm_year + 1900;
    int month = ltime->tm_mon + 1;
    int day = ltime->tm_mday;

    boost::gregorian::date d(year, month, day);  
    double price = getPrice(date);         
  }
}

Conversion between v8::value to date

1 Answers1