index.js

const chromium =  require("chrome-aws-lambda");
const puppeteer = require("puppeteer-core");

exports.handler = async (event) => {
  console.log(event.body);

  const eventBody = JSON.parse(event.body);
  const executablePath = event.isOffline
    ? "./node_modules/puppeteer/.local-chromium/mac-674921/chrome-mac/Chromium.app/Contents/MacOS/Chromium"
    : await chromium.executablePath;

  const browser = await puppeteer.launch({
    args: chromium.args,
    executablePath
  });

  try {
    const page = await browser.newPage();

    const pageLoadOptions = {
      waitUntil: ["networkidle0", "load", "domcontentloaded"]
    };

    if (eventBody.url) {
      await page.goto(eventBody.url, pageLoadOptions);
    } else if (eventBody.html) {
      await page.setContent(eventBody.html, pageLoadOptions);
    } else {
      return {
        statusCode: 400,
        headers: {
          "Content-type": "application/json",
        },
        body: JSON.stringify("Must provide either `html` or `url` on the request body")
      };
    }  

    const pdfOptions = Object.assign(
      {
        printBackground: true,
        format: 'A4',
        margin: { top: '0.4in', right: '0.4in', bottom: '0.4in', left: '0.4in' }
      },
      eventBody.options
    );

    const pdfStream = await page.pdf(pdfOptions);

    return {
      statusCode: 200,
      isBase64Encoded: true,
      headers: {
        "Content-type": "application/pdf"
      },
      body: pdfStream.toString("base64")
    };
  } finally {
    await browser.close();
  }
};