Raspberry Pi node.js I run the code, writes GPIO port (pin) is not defined?

Question

Node.js

Please help, I have a raspberry Pi with node.js installed and everything else that is needed and not so much. As well as an LED connected to the GPIO ports (GPIO4 (P1-07) and Ground (P2-06)). I run a code that should, in theory, make it blink the LED (+ allow them to still manage over the Internet from the specified site):

var socket = require('socket.io-client')('http://bk-it.ru:3141');
var gpio = require('rpi-gpio');
var fs = require('fs');

// hack due to error
fs.exists = require('path').exists;
var async = require('async');

// pin GPIO4
var pin = 7;

// current fps
var piFps = 2;
var currentValue = false;
var timemanager;


var set0 = function(err, results) {
    if (err)
        console.log(err);
    console.log('Pin ' + pin + ' closed');
    directWrite(pin, false, function() {
        clearTimeout(timemanager);
    });
};

var stopblink = true;

var blinkexec = function() {
    delayedWrite(7, true, function() {
        delayedWrite(7, false, blinkexec)
    });
};

var blink = function(err, results) {
    if (err)
        console.log(err);
    console.log('Pin ' + pin + ' blinking');
    blinkexec();
};


function directWrite(pin, value, callback) {
    return gpio.write(pin, value, callback);

}
function delayedWrite(pin, value, callback) {
    var delay = Math.round(1000 / piFps / 2);
    
    clearTimeout(timemanager);
    timemanager = setTimeout(function() {
        directWrite(pin, value, callback);
    }, delay);
}


var release = function() {
    console.log('Writes complete, pause then unexport pins');
    setTimeout(function() {
        gpio.destroy(function() {
            console.log('Closed pins, now exit');
            return process.exit(0);
        });
    }, 500);
};

In general, this is what it gives out:
PS I understand that the translation of the error "port is not defined." I'm a teapot :)

Answer 1

I understand that the translation of the error "port is not defined"

The error is not about the port, but about the variable called "pin".