Settings Manager for Outlook Add-in, , written in JavaScript - MS code converted into reusable

SettingsManager.js

var settingsManager = (function () {
    "use strict";

    var settingsManager = {};
    var _settings;

    settingsManager.initialize = function () {

        //global for custom property
        _settings = Office.context.roamingSettings;

        settingsManager.checkPropertyValue = function (propertyToManage, value) {
            var check = _settings.get(propertyToManage);
            if (check == null || typeof check == 'undefined') {
                this.setAddInSetting(propertyToManage, value);
                check = value;
            }
            return check;
        };

        // Set a roaming setting
        settingsManager.setAddInSetting = function (propertyToManage, value) {
            _settings.set(propertyToManage, value);
            _settings.saveAsync(saveAddInSettingsCallback);
        };

        // Remove an add-in setting.
        settingsManager.removeAddInSetting = function (propertyToManage) {
            _settings.remove(propertyToManage);
            _settings.saveAsync(saveAddInSettingsCallback);
        };

        // Callback method after saving custom roaming settings.
        function saveAddInSettingsCallback (asyncResult) {
            if (asyncResult.status == Office.AsyncResultStatus.Failed) {
                app.showNotification("Save Settings for" + propertyToManage, asyncResult.error.message);
            }
        }
    };
    return settingsManager;
})();