app.js

// Require npm modules
const express = require('express'),
      logger = require('morgan'),
      bodyParser = require('body-parser');

var app = module.exports = express();

const routes = require('./src/config/routes');

// Use morgan to log connections, status, and errors in console
app.use(logger('dev'));
// Use body-parser to catch params sended as url encoded and json
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());

// Call routes from the root path
app.use('', routes);

// Start server on port 3000
app.listen(3000, () => {
});

Crawler.js

const puppeteer = require('puppeteer');

async function posts () {
  const browser = await puppeteer.launch({ headless: true });
  const page = await browser.newPage();
  await page.goto('https://www.milenio.com/ultima-hora');
  await page.waitForSelector("[class='content']");
  let wallData = await page.evaluate(e => {
    window.scrollTo(0, 500);
    // Get all containers with the class equal to lr-row-news and create an array from them
    let elements = Array.from(document.querySelectorAll("[class='lr-row-news']"));
    // Iterate through all found items
    let posts = elements.map(cont => {
      // Searching elements by its parent classes
      let elTitle = cont.querySelector(".title-container > .title");
      let elContent = cont.querySelector(".title-container > .summary > span");
      let elDateTime = cont.querySelector("[class='hour']");
      let elPostLink = cont.querySelector(".title-container > .title > a");
      
      // Return JSON with the text inside the found elements
      return {
        title: (elTitle && elTitle.innerText) ? elTitle.innerText.replace('\n', ' ') : 'Not found',
        content: (elContent && elContent.innerText) ? elContent.innerText.replace('\n', ' ') : "No content found",
        created_at: (elDateTime && elDateTime.innerText) ? elDateTime.innerText.replace('\n', ' ') : "No content found",
        link: (elPostLink && elPostLink.href) ? elPostLink.href : 'Not link',        
        provider: 'MILENIO'
      }
    })
    return posts
  })

  await page.goto('https://elpais.com/tag/mexico/a');
  await page.waitForSelector("[class='articulos articulos_cuerpo']");
  wallData = [...wallData, ...(await page.evaluate(e => {
    window.scrollTo(0, 500);
    let elements = Array.from(document.querySelectorAll("div[class='articulo__interior']"));
    let posts = elements.map(cont => {
      let elTitle = cont.querySelector(".articulo-titulo");
      let elContent = cont.querySelector(".articulo-entradilla");
      let elDateTime = cont.querySelector(".articulo-metadatos > time");
      let elPostLink = cont.querySelector(".articulo-titulo > a");

      return {
        title: (elTitle && elTitle.innerText) ? elTitle.innerText.replace('\n', ' ') : 'Not found',
        content: (elContent && elContent.innerText) ? elContent.innerText.replace('\n', ' ') : "No content found",
        created_at: (elDateTime && elDateTime.innerText) ? elDateTime.innerText.replace('\n', ' ') : "No content found",
        link: (elPostLink && elPostLink.href) ? elPostLink.href : 'Not link',
        provider: 'EL PAÍS'
      }
    })
    return posts;
  }))]

  return wallData
}

module.exports = {
  Crawler: function (app) {
    constructor()
    {
    }
    this.posts = posts
  }
}

news.js

// Require Crawler model
const Crawler = require('../models/Crawler').Crawler;
// Creates an instance of the crawler
const principalCrawler = new Crawler()

class NewsController {
  /* 
    Asynchronous method that takes the parameters
    of the router.get callback (request, response)
  */
  async all (_req, res) {
    // Set Content-Type header to application/json
    res.setHeader('Content-Type', 'application/json');
    // Call posts method from Crawler model and return its value 
    res.send(JSON.stringify(await principalCrawler.posts()));
  }
}

module.exports = NewsController

routes.js

/*
  NewsController: contains the response that will be returned.
  NewsInstance:   instance of NewsController
  express:        require express to access Router
*/
const NewsController = require('../controllers/news'),
      NewsInstance = new NewsController(),
      express = require('express'),
      router = express.Router();

// Catch root path
router.get('/', (_req, res) => {
  res.send('Root page')
});

// Catch /news path and executes method all of NewsController
router.get('/news', NewsInstance.all);

// Returns router
module.exports = router;