export function register()

in src/serviceWorker.js [32:64]

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

export function register(config) {
	if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
		// The URL constructor is available in all browsers that support SW.
		const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href);
		if (publicUrl.origin !== window.location.origin) {
			// Our service worker won't work if PUBLIC_URL is on a different origin
			// from what our page is served on. This might happen if a CDN is used to
			// serve assets; see https://github.com/facebook/create-react-app/issues/2374
			return;
		}

		window.addEventListener('load', () => {
			const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;

			if (isLocalhost) {
				// This is running on localhost. Let's check if a service worker still exists or not.
				checkValidServiceWorker(swUrl, config);

				// Add some additional logging to localhost, pointing developers to the
				// service worker/PWA documentation.
				navigator.serviceWorker.ready.then(() => {
					console.log(
						'This web app is being served cache-first by a service ' +
						'worker. To learn more, visit https://bit.ly/CRA-PWA'
					);
				});
			} else {
				// Is not localhost. Just register service worker
				registerValidSW(swUrl, config);
			}
		});
	}
}