index.js

const fs = require('fs-extra')
const express = require('express')
const nunjucks = require('nunjucks')
const puppeteer = require('puppeteer')
const { v4: uuidv4 } = require('uuid')

const app = express()
app.use(express.json())
app.use(express.urlencoded({ extended: true }))

nunjucks.configure('views', {
  autoescape: true,
  express: app,
  noCache: false
})

let messages = {};

app.listen(3000, () => {
  console.log('server running on port 3000')
})

app.get('/url', (req, res, next) => {
  res.json(["Tony", "Lisa", "Michael", "Ginger", "Food"])
})

app.post('/messages', (req, res) => {
  const id = uuidv4()
  const message = {
    id,
    text: req.body.text
  }

  messages[id] = message

  return res.send(message)
})

app.get('/messages', (req, res) => {
  res.send(messages)
})

app.post('/invoice', (req, res) => {
  (async () => {
    const html = nunjucks.render('index.html', { foo: 'Ka Wing is awesome' })
    await fs.writeFile('generate.html', html)
    createPdf('')
    res.send(html)
  })()
})

function createPdf(html) {
  (async () => {
    console.log('createPDF')
    const browser = await puppeteer.launch();
    const page = await browser.newPage();
    // Emitted when the DOM is parsed and ready (without waiting for resources)
    page.once('domcontentloaded', () => console.info('✅ DOM is ready'));

    // Emitted when the page is fully loaded
    page.once('load', () => console.info('✅ Page is loaded'));

    // Emitted when the page attaches a frame
    page.on('frameattached', () => console.info('✅ Frame is attached'));

    // Emitted when a frame within the page is navigated to a new URL
    page.on('framenavigated', () => console.info('👉 Frame is navigated'));

    // Emitted when a script within the page uses `console.timeStamp`
    page.on('metrics', data => console.info(`👉 Timestamp added at ${data.metrics.Timestamp}`));

    // Emitted when a script within the page uses `console`
    page.on('console', message => console[message.type()](`👉 ${message.text()}`));

    // Emitted when the page emits an error event (for example, the page crashes)
    page.on('error', error => console.error(`❌ ${error}`));

    // Emitted when a script within the page has uncaught exception
    page.on('pageerror', error => console.error(`❌ ${error}`));

    // Emitted when a script within the page uses `alert`, `prompt`, `confirm` or `beforeunload`
    page.on('dialog', async dialog => {
      console.info(`👉 ${dialog.message()}`);
      await dialog.dismiss();
    });

    // Emitted when a new page, that belongs to the browser context, is opened
    page.on('popup', () => console.info('👉 New page is opened'));

    // Emitted when the page produces a request
    page.on('request', request => console.info(`👉 Request: ${request.url()}`));

    // Emitted when a request, which is produced by the page, fails
    page.on('requestfailed', request => console.info(`❌ Failed request: ${request.url()}`));

    // Emitted when a request, which is produced by the page, finishes successfully
    page.on('requestfinished', request => console.info(`👉 Finished request: ${request.url()}`));

    // Emitted when a response is received
    page.on('response', response => console.info(`👉 Response: ${response.url()}`));

    // Emitted when the page creates a dedicated WebWorker
    page.on('workercreated', worker => console.info(`👉 Worker: ${worker.url()}`));

    // Emitted when the page destroys a dedicated WebWorker
    page.on('workerdestroyed', worker => console.info(`👉 Destroyed worker: ${worker.url()}`));

    // Emitted when the page detaches a frame
    page.on('framedetached', () => console.info('✅ Frame is detached'));

    // Emitted after the page is closed
    page.once('close', () => console.info('✅ Page is closed'));
    console.log('yoooooo')
    await page.goto('https://example.com', { waitUntil: 'networkidle2' });
    await page.pdf({ path: 'invoice.pdf', format: 'A4' });
    console.log('done')
    await browser.close();
  })();
}