The document describes how to configure a service worker to cache assets and network requests to improve performance for a web application. It shows code for registering a service worker, precaching assets using Workbox, transforming precached URLs to include cache-busting query strings, and configuring runtime caching for API requests using a network-first strategy with a 30-day cache expiration.
![Workboxで始める Service Worker](https://cdn-ak-scissors.b.st-hatena.com/image/square/b10712fc1dca4b4f2c78f94904412b110475a93a/height=288;version=1;width=512/https%3A%2F%2Fcdn.slidesharecdn.com%2Fss_thumbnails%2Fstartserviceworkerbyworkbox-180316090157-thumbnail.jpg%3Fwidth%3D640%26height%3D640%26fit%3Dbounds)