local-observable-store/index.js

An observable data-store that persists in local storage

/**
* @license local-observable-store https://github.com/cosmosio/local-observable-store
*
* The MIT License (MIT)
*
* Copyright (c) 2014-2015 Olivier Scherrer <pode.fr@gmail.com>
*/
"use strict";

var Store = require("observable-store"),
    loop = require("simple-loop");

/**
 * @class
 * LocalStore is an Emily's Store that can be synchronized with localStorage
 * Synchronize the store, reload your page/browser and resynchronize it with the same value
 * and it gets restored.
 * Only valid JSON data will be stored
 */
function LocalStoreConstructor() {

    /**
     * The name of the property in which to store the data
     * @private
     */
    var _name = null,

    /**
     * The localStorage
     * @private
     */
    _localStorage = localStorage;

    /**
     * Saves the current values in localStorage
     * @private
     */
    function persistLocalStorage() {
        _localStorage.setItem(_name, this.toJSON());
    }

    /**
     * Override default localStorage with a new one
     * @param local$torage the new localStorage
     * @returns {Boolean} true if success
     * @private
     */
    this.setLocalStorage = function setLocalStorage(local$torage) {
        if (local$torage && typeof local$torage.setItem == "function") {
            _localStorage = local$torage;
            return true;
        } else {
            return false;
        }
    };

    /**
     * Get the current localStorage
     * @returns localStorage
     * @private
     */
    this.getLocalStorage = function getLocalStorage() {
        return _localStorage;
    };

    /**
     * Synchronize the store with localStorage
     * @param {String} name the name in which to save the data
     * @returns {Boolean} true if the param is a string
     */
    this.sync = function sync(name) {
        var json;

        if (typeof name == "string") {
            _name = name;
            json = JSON.parse(_localStorage.getItem(name));

            loop(json, function (value, idx) {
                if (!this.has(idx)) {
                    this.set(idx, value);
                }
            }, this);

            persistLocalStorage.call(this);

            // Watch for modifications to update localStorage
            this.watch("added", persistLocalStorage, this);
            this.watch("updated", persistLocalStorage, this);
            this.watch("deleted", persistLocalStorage, this);
            return true;
        } else {
            return false;
        }
    };
}

module.exports = function LocalStoreFactory(init) {
    LocalStoreConstructor.prototype = new Store(init);
    return new LocalStoreConstructor();
};