ready property
      
      JSPromise<ServiceWorkerRegistration> 
      get
      ready
      
    
    
The ready read-only property of
the ServiceWorkerContainer interface provides a way of delaying code
execution until a service worker is active. It returns a Promise that
will never reject, and which waits indefinitely until
the ServiceWorkerRegistration associated with the current page has
an ServiceWorkerRegistration.active worker. Once that
condition is met, it resolves with
the ServiceWorkerRegistration.
Implementation
external JSPromise<ServiceWorkerRegistration> get ready;