Nodejs: get filename of caller function

I wonder how-to get an absolute path of a caller of a function?

Let say that:

in file a.js I call b(); b() is a function defined in file b.js. a.jsrequires b . So how do I get a.js absolute path from b.js in node?

This is an example how to use stacktrace to find caller file in node

function _getCallerFile() {
    var filename;

    var _pst = Error.prepareStackTrace
    Error.prepareStackTrace = function (err, stack) { return stack; };
    try {
        var err = new Error();
        var callerfile;
        var currentfile;

        currentfile = err.stack.shift().getFileName();

        while (err.stack.length) {
            callerfile = err.stack.shift().getFileName();

            if(currentfile !== callerfile) {
                filename = callerfile;
                break;
            }
        }
    } catch (err) {}
    Error.prepareStackTrace = _pst;

    return filename;
}