export function register()

in packages/typescript-example/src/serviceWorker.js [23:55]

• 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 http://bit.ly/CRA-PWA"
                    );
                });
            } else {
                // Is not localhost. Just register service worker
                registerValidSW(swUrl, config);
            }
        });
    }
}