如果要註銷(uninstall)PWA 的 service worker，可以用以下的方法。
serviceWorkerRegistration.unregister().then(function(boolean) {
});
範例：
if ('serviceWorker' in navigator) {
navigator.serviceWorker.register('/sw-test/sw.js', {scope: 'sw-test'}).then(function(registration) {
// registration worked
console.log('Registration succeeded.');
registration.unregister().then(function(boolean) {
// if boolean = true, unregister is successful
});
}).catch(function(error) {
// registration failed
console.log('Registration failed with ' + error);
});
};
navigator.serviceWorker.getRegistrations().then(function(registrations) {
for(let registration of registrations) {
registration.unregister()
} })
