const puppeteer = require('puppeteer');
(async() => {
  const browser = await puppeteer.launch({headless: false});

  const page = await browser.newPage();
  await page.goto('https://example.com');
  await page.waitForFunction((args) => {
     
    // some tests to show what is happeneing.
    console.log([
      args, // should show args
      arguments, // should not have 0 elements
      Array.isArray(args), // should return True
      Array.isArray([1, 2, 3, 4]) // should return True
    ]);

    return Array.isArray(args);
  }, [1, 2, 3, 4]); // no matter what you pass, it's still undefined;

  await page.screenshot({path: 'example.png'});
  //browser.close();
})();

await page.evaluate((args) => {
    // shows `ReferenceError: arguments is not defined`
    console.log(arguments)

    // runs properly
    console.log([
      args,
      Array.isArray(args),
      Array.isArray([1, 2, 3, 4])
    ]);

    return Array.isArray(args);
  }, [1, 2, 3, 4]);