The scope of a Service Worker defines the content it can control, specifically which requests it can intercept and handle. It is defined at registration, and typically, a Service Worker is limited to requests within its registration path and subpaths.
For instance, if you register a Service Worker at /app/, its scope is restricted to /app/ and its subpaths. Consequently, it can intercept requests for paths like /app/, /app/home, /app/settings, but not for the root path / or paths such as /other.
This scope restriction ensures that the Service Worker does not interfere with unrelated pages or applications, offering a secure method to limit its control.
Consider an e-commerce site: if it registers a Service Worker at the root with the root path as its scope, it can manage all pages. However, if the site aims to use the Service Worker solely for product directory pages to cache content and enable offline support, it can register a dedicated Service Worker at /products/ with the scope restricted to this subdirectory. Thus, the Service Worker will only handle requests under /products/ and not affect other pages.