Web Worker Offloading
Offloads select JavaScript execution to a Web Worker to reduce work on the main thread and improve the Interaction to Next Paint (INP) metric.
Plugin info
Maintenance & Compatibility
Maintenance score
Actively maintained • Last updated 28 days ago • Support resolved 0% • 2 reviews
Is Web Worker Offloading abandoned?
Likely maintained (last update 28 days ago).
Compatibility
Developers
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Description
This plugin offloads JavaScript execution to a Web Worker, improving performance by freeing up the main thread. This should translate into improved Interaction to Next Paint (INP) scores.
⚠ This functionality is experimental. ⚠
In order to opt in a script to be loaded in a worker, simply add worker script data to a registered script. For example,
if you have a script registered with the handle of foo, opt-in to offload it to a web worker by doing:
wp_script_add_data( 'foo', 'worker', true );
Unlike with the script loading strategies (async/defer), any inline before/after scripts associated with the worker-offloaded registered script will also be offloaded to the worker, whereas with the script strategies an inline after script would block the script from being delayed.
Otherwise, the plugin currently ships with built-in integrations to offload Google Analytics to a web worker for the following plugin:
Please monitor your analytics once activating to ensure all the expected events are being logged. At the same time, monitor your INP scores to check for improvement.
This plugin relies on the Partytown 🎉 library by Builder.io, released under the MIT license. This library is in beta and there are quite a few open bugs.
The Partytown configuration can be modified via the plwwo_configuration filter. For example:
However, not all of the configuration options can be serialized to JSON in this way, for example the resolveUrl configuration is a function. To specify this, you can add an inline script as follows.
{
if (type === 'script') {
const proxyUrl = new URL('https://my-reverse-proxy.example.com/');
proxyUrl.searchParams.append('url', url.href);
return proxyUrl;
}
return url;
},
};
JS,
'before'
);
}
);
There are also many configuration options which are not documented, so refer to the TypeScript definitions.
Installation
Frequently Asked Questions
If you find that your offloaded scripts aren’t working while also seeing a 404 error in the console for a file at /wp-content/plugins/web-worker-offloading/build/partytown-sandbox-sw.html?1727389399791 then it’s likely you have Chrome DevTools open with the “Bypass for Network” toggle enabled in the Application panel.
The Performance team and WordPress community take security bugs seriously. We appreciate your efforts to responsibly disclose your findings, and will make every effort to acknowledge your contributions.
To report a security issue, please visit the WordPress HackerOne program.
Contributions are always welcome! Learn more about how to get involved in the Core Performance Team Handbook.
The plugin source code is located in the WordPress/performance repo on GitHub.
Review feed
Screenshots
Changelog
0.2.0
Enhancements
- Integrate Web Worker Offloading with Google Site Kit. (1686)
- Integrate Web Worker Offloading with Rank Math SEO. (1685)
- Serve unminified scripts when
SCRIPT_DEBUGis enabled. (1643)
Bug Fixes
- Fix tracking events like add_to_cart in WooCommerce integration. (1740)
0.1.1
Enhancements
- Add Web Worker Offloading meta generator. (1598)
0.1.0
- Initial release.