Puppeteer Error: Unhandled Promise Rejection Warning

Other Questions Puppeteer
1

I recently switched from my desktop to my laptop, and now whenever I attempt to execute a Puppeteer script, I encounter the following error:

(node:69) UnhandledPromiseRejectionWarning: TimeoutError: Connection to the browser timed out after 30000 ms! Only the specified version of Chrome is guaranteed to function correctly.
    at Timeout.onTimeout (/path/to/your/project/node_modules/puppeteer/lib/cjs/puppeteer/node/BrowserRunner.js:208:20)
    at listOnTimeout (internal/timers.js:554:17)
    at processTimers (internal/timers.js:497:7)
(node:69) UnhandledPromiseRejectionWarning: A promise was rejected but not caught. This can occur when excluding a catch block in an async function or failing to handle a promise rejection with .catch(). To ensure the Node process exits correctly on unhandled rejections, apply the CLI option `--unhandled-rejections=strict`.
(node:69) [DEP0018] DeprecationWarning: Unhandled promise rejections will become fatal in future versions of Node.js.

How can I resolve this issue?

2

Hi Hazel,

The error you're encountering often happens when Puppeteer can't connect to Chrome within the specified timeout period. Here’s how you can resolve this:

  1. Ensure Chrome is Installed: Make sure Chrome is properly installed on your laptop. Puppeteer usually downloads its own version, but ensure there are no conflicts with versions.
  2. Increase Timeout: Sometimes scripts take longer to connect. Increase the timeout period as follows:

const browser = await puppeteer.launch({
  args: ['--no-sandbox', '--disable-setuid-sandbox'],
  headless: true,
  timeout: 60000 // Increase this value to avoid timeout errors
});
  1. Error Handling: Always include .catch() to manage unhandled promises:

(async () => {
  try {
    const browser = await puppeteer.launch();
    const page = await browser.newPage();
    // Your script here...
    await browser.close();
  } catch (error) {
    console.error('Error encountered:', error);
  }
})();
  1. Check Permission and Firewall: Ensure that your firewall or security settings are not blocking Puppeteer or its dependencies.

Implement these steps and run your script. This should resolve the issue and make your Puppeteer script execute without errors.

Let me know if you need further help!

3

While the previous suggestions are helpful, there are a few additional steps you can consider to address the Unhandled Promise Rejection error in Puppeteer:

  1. Version Compatibility: Ensure that your version of Puppeteer is compatible with the installed Node.js version. Check the Puppeteer documentation for any version-specific issues that might need addressing.
    2. <li><strong>Network Conditions:</strong> If you're on a laptop, check if any network settings or internet security software are interfering with the connection. Occasionally, such settings may prevent Puppeteer from starting or connecting to its browser instance.</li>

<li><strong>Node.js Version Update:</strong> Since your error mentions a warning about unhandled promise rejections becoming fatal in future Node.js releases, it might be useful to update to a version where promises rejections are handled more gracefully. This can help reveal issues in case of future updates.</li>

<li><strong>Diagnostic Logs:</strong> Enable verbose logging to get additional insights into what might be causing the timeout error. You can do this by adding <code>dumpio: true</code> to the Puppeteer launch options:</li>


const browser = await puppeteer.launch({
  args: ['--no-sandbox', '--disable-setuid-sandbox'],
  headless: true,
  timeout: 60000,
  dumpio: true
});

By incorporating the above practices, you can identify and troubleshoot the root cause of the Puppeteer error on your laptop. If the issue persists, consider setting up a minimal reproducible example and reviewing the Puppeteer GitHub issues for related cases.