比较从参数传递的字符串

Question

Creating a node.js addon with C++. I want to check if the passed parameter is hi .

The node app:

addon.Hello("hi");

The C++:

if (args[0]->ToString() != "hi") {
  ThrowException(Exception::TypeError(String::New("Sunday morning rain is falling...")));
  return scope.Close(Undefined());
}

But it keeps giving me the errors:

../xxx.cc: In static member function 'static v8::Handle xxx::New(const v8::Arguments&)': ../xxx.cc:41:29: error: no match for 'operator!=' (operand types are 'v8::Local' and 'const char [6]') if (args[0]->ToString() != "hi") { ^

Answer 1

ToString() returns a String object. You can get a C string from that with something like char* foo = *String::Utf8Value(args[0]->ToString()); .

Answer 2

Yeah I had this same problem, this seems to compile:

  using namespace std;

  v8::String::Utf8Value arg2(args[2]->ToString());

  if (strcmp(*arg2, "true") != 0 && strcmp(*arg2, "false") != 0) {
        Nan::ThrowTypeError("Third argument to 'replace-line' must be a string representing whether to find or replace.");
        return;
   }

   bool isReplace = strcmp(*arg2, "false") == 0 ? false : true;

I basically arrived at my solution via the comments from the other answer, someone needed to just update a new answer with the actual solution which is what I have done here (I hope).

Answer 3

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

String::Utf8Value tmp(args[0]->ToString());
arg0 = std::string(*tmp);
//then you can compare string using "== or > or <"
if(arg0 == "hi")
{
    ...
}