Simple NodeJS Link Crawler

crawl.js

'use strict';

import Crawler from "simplecrawler";
import fs from 'fs';

Crawler.crawl("http://www.google.com").on("fetchcomplete", (queueItem, responseBuffer, response) => {
  console.log("Completed fetching resource:", queueItem.url);
  
  if (queueItem.url.indexOf('png') > 0 || queueItem.url.indexOf('jpg') > 0 || queueItem.url.indexOf('gif') > 0 || queueItem.url.indexOf('jpeg') > 0) {
    let filename = queueItem.url.substring(queueItem.url.lastIndexOf('/')+1);  
    fs.writeFile(__dirname + "/assets/images/"+filename, responseBuffer, (err) => {
      console.log(err);
    });
  }

  fs.appendFileSync(__dirname + '/results.txt', queueItem.url + '\r\n');
});