The FetchEvent
class is a fetch action dispatched on the service worker. It contains details about requests as well as responses. It provides all important FetchEvent.reponseWith()
methods, which we can use to provide a response back to the page that is controlled by the service worker.
To get started with service workers, you will need to have the service worker experiment feature turned on in your browser settings. If you have not done this yet, refer to the first recipe of Chapter 1, Learning Service Worker Basics: Setting up service workers. Service workers only run across HTTPS. To find out how to set up a development environment to support this feature, refer to the following recipes of Chapter 1, Learning Service Worker Basics: Setting up GitHub pages for SSL, Setting up SSL for Windows, and Setting up SSL for Mac.