IndexedDB in Backbone
As the IndexedDB API is more complex than localStorage, it will be more difficult to create an IndexedDB driver for Backbone as we did with localStorage; in this section, you will use what you have learned about IndexedDB in order to build a driver for Backbone.
The driver should open a database and initialize the stores when it is created for the first time:
// indexedDB/dataStore.js
'use strict';
var Backbone = require('backbone');
const ID_LENGTH = 10;
var contacts = [
// ...
];
class DataStore {
constructor() {
this.databaseName = 'contacts';
}
openDatabase() {
var defer = Backbone.$.Deferred();
// If a database connection is already active use it,
// otherwise open a new connection
if (this.db) {
defer.resolve(this.db);
} else {
let request = indexedDB.open(this.databaseName, 1);
request.onupgradeneeded = () => {
let db = request.result;
this.createStores(db);
};
request.onsuccess = () => {
// Cache recently...