Save a PDF using Puppeteer given a URL. Run with first argument set to the URL to save as PDF.

save-pdf.js

const fs = require('fs');
const path = require('path');
const url = require('url');
const puppeteer = require('puppeteer');

class Webpage {
	static async generatePDF(url, filename) {
		const browser = await puppeteer.launch({ headless: true });
		const page = await browser.newPage();
		await page.goto(url);

		const pdfConfig = {
			path: filename,
			format: 'A4',
			printBackground: true,
			// Word's default A4 margins
			margin: {
				top: '2.54cm',
				bottom: '2.54cm',
				left: '2.54cm',
				right: '2.54cm'
			},
		};

		await page.emulateMedia('screen');
		const pdf = await page.pdf(pdfConfig);

		await browser.close();

		return pdf;
	}
}

const [, , theURL] = process.argv;

function createUniqueFilename(pathname) {
  const ext = path.extname(pathname);
  let filename = `${path.basename(pathname, ext)}.pdf`;

  let i = 1;
  while (fs.existsSync(filename)) {
    filename = `${path.basename(pathname, ext)}_${i}.pdf`;
    i += 1;
  }

  return filename;
}

(async() => {
	const urlParsed = url.parse(theURL);
  const filename = createUniqueFilename(urlParsed.pathname);

  try {
    console.log(`Downloading ${theURL} as ${filename}`);
    await Webpage.generatePDF(theURL, filename);
  } catch (err) {
    console.error(err.toString());
    process.exit(1);
  }
})();