enhancing-comment-form__10.js

importScripts('idb-keyval.js');

const VERSION = 'v1';

self.addEventListener('install', function (e) {
    self.skipWaiting();
    e.waitUntil(
        caches.open(VERSION).then(function (cache) {
            return cache.addAll([
                './',
                './index.html',
                '../style.css',
                'enhanced.js'
            ]);
        })
    );
});

self.addEventListener('fetch', function (e) {
    let request = e.request;
    if (request.method !== 'GET') {
        return;
    }
});

self.addEventListener('activate', function () {
    if (self.clients && clients.claim) {
        clients.claim();
    }
});

self.addEventListener('sync', function (e) {
    if (e.tag == 'form-post') {
        e.waitUntil(postComment());
    }
});

function postComment () {
    let formData = new FormData();

    idbKeyval.get('name').then(function (data) {
        formData.append('name', data);
    });

    idbKeyval.get('comment').then(function (data) {
        formData.append('comment', data);
    });

    fetch('./save', {
        method: 'POST',
        mode: 'cors',
        body: formData
    }).then(function (response) {
        return response;
    }).then(function (text) {
        send_message_to_all_clients('success');
    }).catch(function (error) {
        send_message_to_all_clients('error');
    });
}

function send_message_to_client (client, msg) {
    return new Promise(function (resolve, reject) {
        var msg_chan = new MessageChannel();

        msg_chan.port1.onmessage = function (e) {
            if (e.data.error) {
                reject(e.data.error);
            } else {
                resolve(e.data);
            }
        };

        client.postMessage(msg, [msg_chan.port2]);
    });
}

function send_message_to_all_clients (msg) {
    clients.matchAll().then(clients => {
        clients.forEach(client => {
            send_message_to_client(client, msg).then(
                msg => console.log('Сообщение из сервис-воркера: ' + msg)
            );
        });
    });
}