We cannot let photo always keep caching new data without clean the old data. If message is not display on the page anymore, we want to clean it. And also every 5 mins we want to clean the photo data.

 

export default function IndexController(container) {    this._container = container;    this._postsView = new PostsView(this._container);    this._toastsView = new ToastsView(this._container);    this._lostConnectionToast = null;    this._dbPromise = openDatabase();    this._registerServiceWorker();    this._cleanImageCache();    var indexController = this;    setInterval(function () {        indexController._cleanImageCache();    }, 1000 * 60 * 5);    this._showCachedMessages().then(function () {        indexController._openSocket();    });}

 

_leanImageCache():

• First, go to idb, get all the writtrs from the db and get the photos which we want to keep
• Then open the photo cache and check the url exists in the list, if not then delete it.

IndexController.prototype._cleanImageCache = function () {    return this._dbPromise.then(function (db) {        if (!db) return;        // TODO: open the 'wittr' object store, get all the messages,        // gather all the photo urls.        //        // Open the 'wittr-content-imgs' cache, and delete any entry        // that you no longer need.        var photosToKeep = [];        var tx = db.transaction('wittrs');        return tx.objectStore('wittrs').getAll()            .then(function(messages){                messages.forEach(function(message){                    if(message.photo){                        photosToKeep.push(message.photo);                    }                });                return caches.open('wittr-content-imgs');            })            .then(function(cache){                return cache.keys().then(function(requests){                    requests.forEach(function(request){                        var url = new URL(request.url);                        if(!photosToKeep.includes(url.pathname)){                            cache.delete(request);                        }                    })                })            });    });};