public/lib/local-storage-adapter.js

/**
 * Adapter wrapping browser localStorage.
 * Values are namespaced by default to avoid name collisions.
 */

import angular from 'angular';

angular.module('wfLocalStorageAdapter', [])
    .factory('wfLocalStorageAdapter', ['$log', function ($log) {

        var DEFAULT_PREFIX = 'wf_';

        class LocalStorageAdapter {

            /**
             * Retrieve a value from localStorage.
             * @throws {Error} If localStorage is unavailable.
             * @return {String}
             */
            get(key, prefix = DEFAULT_PREFIX) {
                return window.localStorage.getItem(prefix + key);
            }

            /**
             * Retrieve and parse JSON stringified object from local storage.
             * @return {Object}
             */
            getObject(key, prefix) {
                var raw = this.get(key, prefix);

                if (!raw) {
                    return;
                }

                return JSON.parse(raw);
            }

            /**
             * Store a value in localStorage.
             * @throws {Error} If localStorage is unavailable or full.
             */
            set(key, value, prefix = DEFAULT_PREFIX) {
                if (typeof(value) == 'object') {
                    value = JSON.stringify(value);
                }

                window.localStorage.setItem(prefix + key, value);
            }
        }

        return new LocalStorageAdapter();

    }]);