coupon.js

const { chromium } = require("playwright");
const assert = require("chai").assert;
const fs = require('fs');

(async () => {
  const browser = await chromium.launch();
  const page = await browser.newPage();
  
  let rawdata = fs.readFileSync('books.json');
  const bookList = JSON.parse(rawdata)

  let foundList = bookList

  await page.goto('https://danube-webshop.herokuapp.com//')
  
  // await page.click('.topbar > input')
  // await page.type('.topbar > input', 'for')
  // await page.click('#button-search')
  
  await page.waitForSelector('.shop-content > ul > .preview:nth-child(1) > .preview-title')

  // halt immediately if results do not equal expected number
  let resultsNumber = (await page.$$('.preview-title')).length
  assert.equal(resultsNumber, bookList.length)

  // remove every element found from the second array...
  for  (i = 0; i < resultsNumber; i++) {
      const bookTitle = await page.$eval(`.preview:nth-child(${i+1}) > .preview-title`, e => e.innerText)
      const bookAuthor = await page.$eval(`.preview:nth-child(${i+1}) > .preview-author`, e => e.innerText)

       foundList = foundList.filter(e => (!((e.title === bookTitle) && (e.author === bookAuthor))))
 
  }
  
  // ...then assert that the second array is now empty
  assert.equal(foundList.length, 0)

  await browser.close()
})()

example.js

const puppeteer = require("puppeteer");

(async () => {
  const puppeteer = require("puppeteer");
  const browser = await puppeteer.launch({ headless: false });
  const page = await browser.newPage();
  const navigationPromise = page.waitForNavigation();

  await page.goto("https://www.amazon.com/");

  await page.setViewport({ width: 1200, height: 873 });

  await page.waitForSelector("#nav-search #twotabsearchtextbox");
  await page.click("#nav-search #twotabsearchtextbox");

  let randomSixNum = Math.floor(Math.random() * 89999 + 100000);
  await page.type("#twotabsearchtextbox", randomSixNum.toString());
  await navigationPromise;

  await browser.close();
})();