function registerValidSW()

in src/serviceWorker.js [66:108]
33 lines of code
8 McCabe index (conditional complexity)

function registerValidSW(swUrl, config) {
	navigator.serviceWorker
		.register(swUrl)
		.then(registration => {
			registration.onupdatefound = () => {
				const installingWorker = registration.installing;
				if (installingWorker == null) {
					return;
				}
				installingWorker.onstatechange = () => {
					if (installingWorker.state === 'installed') {
						if (navigator.serviceWorker.controller) {
							// At this point, the updated precached content has been fetched,
							// but the previous service worker will still serve the older
							// content until all client tabs are closed.
							console.log(
								'New content is available and will be used when all ' +
								'tabs for this page are closed. See https://bit.ly/CRA-PWA.'
							);

							// Execute callback
							if (config && config.onUpdate) {
								config.onUpdate(registration);
							}
						} else {
							// At this point, everything has been precached.
							// It's the perfect time to display a
							// "Content is cached for offline use." message.
							console.log('Content is cached for offline use.');

							// Execute callback
							if (config && config.onSuccess) {
								config.onSuccess(registration);
							}
						}
					}
				};
			};
		})
		.catch(error => {
			console.error('Error during service worker registration:', error);
		});
}