Default:
null.
Example:'/'
When making a Singe Page Application, it's common to use AppShell model for it.
To make offline-plugin redirect all unknown navigation requests to a specific cache, specify appShell option, e.g. appShell: '/'.
When using Server Side Rendering with AppShell model, make sure that you do not cache any server rendered data with it. Easiest way would be to make a route which will be serving the HTML file without any server rendered data in it (e.g. ready for client side rendering) and cache that route. Example: appShell: '/app-shell.html'
appShell is baked by cacheMaps option for ServiceWorker and AppCache.FALLBACK option for AppCache.