Dead letter queues are system-generated queues for one or many of the following reasons: for storing messages that could not be delivered, queue length limit exceeded, message length limit exceeded, or a message being rejected by another queue exchange.
In this recipe, we are implementing a dead letter queue in 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: Setting up GitHub pages for SSL, Setting up SSL for Windows, and Setting up SSL for Mac.
Follow these instructions to set up your file structure:
Download all the files from the following location: