function checkValidServiceWorker()

in src/registerServiceWorker.tsx [126:160]

• 31 lines of code
• 5 McCabe index (conditional complexity)

function checkValidServiceWorker (swUrl: string, toasterSupplier: () => (Toaster | null)) {
  // Check if the service worker can be found. If it can't reload the page.
  fetch(swUrl)
    .then((response) => {
      // Ensure service worker exists, and that we really are getting a JS file.
      if (
        response.status === 404 ||
        (response.headers.get('content-type') || '').indexOf('javascript') === -1
      ) {
        // No service worker found. Probably a different app. Reload the page.
        navigator.serviceWorker.ready.then((registration) => {
          return registration.unregister().then(() => {
            window.location.reload()
          })
        }).catch(() => {/* do nothing */})
      } else {
        // Service worker found. Proceed as normal.
        registerValidSW(swUrl, toasterSupplier)
      }
    })
    .catch(() => {
      const toaster = toasterSupplier()
      if (toaster) {
        toaster.show({
          icon: 'offline',
          intent: Intent.PRIMARY,
          message: (
            <React.Fragment>
              No internet connection found. The page is running in offline mode.
            </React.Fragment>
          )
        })
      }
    })
}