Functions that can't execute together

Question

I was recently building a scraper module to get some information with nodejs until I encountered this "little" problem. The modules that I'm using are cheeriojs and request. Actually the module works like a charm if I call only one method at a time. It contains three function and only two of them are exported, this is the code:

'use strict';

var request = require('request'),
    cheerio = require('cheerio'),
    counter = 0;

function find(term, cat, callback) {
  // All the check for the parameters
  scrape("http://.../search.php?search=" + encodeURIComponent(term), cat, callback);
}

function last(cat, callback) {
  // All the check for the parameters
  scrape("http://google.com/", cat, callback);
}

function scrape(url, cat, callback) {
  request(url, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      var $ = cheerio.load(body);
      var result = [];

      var items = $('.foo, .foo2').filter(function() {
        // Condition to filter the resulted items
      });

      items.each(function(i, row) {
        // Had to do another request inside here to scrape other information
        request( $(".newpagelink").attr("href"), function(error, response, body) {
          var name = $(".selector").text(),
              surname = $(".selector2").text(),
              link = cheerio.load(body)('.magnet').attr('href'); // This is the only thing that I'm scraping from the new page, the rest comes from the other "cheerio.load"
        // Push an object in the array
        result.push( { "name": name, "surname": surname, "link": link } );

          // To check when the async requests are ended
          counter++;
          if(counter == items.length-1) {
            callback(null, result);
          }
        });
      });
    }
  });
}

exports.find = find;
exports.last = last;

The problem now, as I was saying, is that if I create a new node script "test.js" and I call only last OR find, it works perfectly! But if I call both the methods consecutively like this:

var mod = require("../index-tmp.js");
mod.find("bla", "blabla", function(err, data) {
    if (err) throw err;
    console.log(data.length + " find");
});
mod.last(function(err, data) {
  console.log(data.length + " last");
});

The results are completely messed up, sometimes the script doesn't even print something, other times print the result of only "find" or "last", and other times returns a cheeriojs error (I won't add here to not mess you up, because probably it's my script's fault). I thought also to repeat the same function two times for both the methods but nothing, the same problems occur... I don't know what else to try, I hope you'll tell me the cause of this behavior!

Answer 1

Your counter variable is global, not specific to each scrape call. It wouldn't work if you called find twice at the same time either, or last.

Move the declaration and initialisation of var counter = 0; into the scrape function, or even better right next to the result and items declarations.