Simon Willison’s Weblog

2 items tagged “serviceworkers”

2021

Introducing Partytown 🎉: Run Third-Party Scripts From a Web Worker (via) This is just spectacularly clever. Partytown is a 6KB JavaScript library that helps you move gnarly poorly performing third-party scripts out of your main page and into a web worker, so they won’t destroy your page performance. The really clever bit is in how it provides sandboxed access to the page DOM: it uses a devious trick where a proxy object provides getters and setters which then make blocking API calls to a separate service worker, using the mostly-forgotten xhr.open(..., false) parameter that turns off the async default for an XMLHttpRequest call. # 23rd September 2021, 6:29 pm

2018

Everyone can now run JavaScript on Cloudflare with Workers. This is such a brilliant piece of software design: Cloudflare took the service workers spec and used it as the basis for their edge-executed JacaScript feature. This means you can run server-side JavaScript in hundreds of edge locations worldwide, applying custom dynamic logic (including additional async cached fetch() calls) with only around 1ms if additional overhead. The pricing model is a steal: $0.50 per million requests with a $5/month minimum. # 13th March 2018, 4:36 pm