localStorageModule.js

define(['Console'], function (Console) {
  "use strict";
  Console.group("Entering localStorageService module.");

  var service = ['$rootScope', function($rootScope) {

    // You should set a prefix to avoid overwriting any local storage variables from the rest of your app
    // e.g. angularLocalStorage.constant('prefix', 'yourAppName');
    var prefix = 'yourAppName';
    // Cookie options (usually in case of fallback)
    // expiry = Number of days before cookies expire // 0 = Does not expire
    // path = The web path the cookie represents
    var cookie =  { expiry:30, path: '/'};

    // If there is a prefix set in the config lets use that with an appended period for readability
    //var prefix = angularLocalStorage.constant;
    if (prefix.substr(-1)!=='.') {
      prefix = !!prefix ? prefix + '.' : '';
    }

    // Checks the browser to see if local storage is supported
    var browserSupportsLocalStorage = function () {
      try {
          return ('localStorage' in window && window['localStorage'] !== null);
      } catch (e) {
          $rootScope.$broadcast('LocalStorageModule.notification.error',e.message);
          return false;
      }
    };

    // Directly adds a value to local storage
    // If local storage is not available in the browser use cookies
    // Example use: localStorageService.add('library','angular');
    var addToLocalStorage = function (key, value) {

      // If this browser does not support local storage use cookies
      if (!browserSupportsLocalStorage()) {
        $rootScope.$broadcast('LocalStorageModule.notification.warning','LOCAL_STORAGE_NOT_SUPPORTED');
        return addToCookies(key, value);
      }

      // 0 and "" is allowed as a value but let's limit other falsey values like "undefined"
      if (!value && value!==0 && value!=="") return false;

      try {
        localStorage.setItem(prefix+key, value);
      } catch (e) {
        $rootScope.$broadcast('LocalStorageModule.notification.error',e.message);
        return addToCookies(key, value);
      }
      return true;
    };

    // Directly get a value from local storage
    // Example use: localStorageService.get('library'); // returns 'angular'
    var getFromLocalStorage = function (key) {
      if (!browserSupportsLocalStorage()) {
        $rootScope.$broadcast('LocalStorageModule.notification.warning','LOCAL_STORAGE_NOT_SUPPORTED');
        return getFromCookies(key);
      }

      var item = localStorage.getItem(prefix+key);
      if (!item) return null;
      return item;
    };

    // Remove an item from local storage
    // Example use: localStorageService.remove('library'); // removes the key/value pair of library='angular'
    var removeFromLocalStorage = function (key) {
      if (!browserSupportsLocalStorage()) {
        $rootScope.$broadcast('LocalStorageModule.notification.warning','LOCAL_STORAGE_NOT_SUPPORTED');
        return removeFromCookies(key);
      }

      try {
        localStorage.removeItem(prefix+key);
      } catch (e) {
        $rootScope.$broadcast('LocalStorageModule.notification.error',e.message);
        return removeFromCookies(key);
      }
      return true;
    };

    // Remove all data for this app from local storage
    // Example use: localStorageService.clearAll();
    // Should be used mostly for development purposes
    var clearAllFromLocalStorage = function () {

      if (!browserSupportsLocalStorage()) {
        $rootScope.$broadcast('LocalStorageModule.notification.warning','LOCAL_STORAGE_NOT_SUPPORTED');
        return clearAllFromCookies();
      }

      var prefixLength = prefix.length;

      for (var key in localStorage) {
        // Only remove items that are for this app
        if (key.substr(0,prefixLength) === prefix) {
          try {
            removeFromLocalStorage(key.substr(prefixLength));
          } catch (e) {
            $rootScope.$broadcast('LocalStorageModule.notification.error',e.message);
            return clearAllFromCookies();
          }
        }
      }
      return true;
    };

    // Checks the browser to see if cookies are supported
    var browserSupportsCookies = function() {
      try {
        return navigator.cookieEnabled ||
          ("cookie" in document && (document.cookie.length > 0 ||
          (document.cookie = "test").indexOf.call(document.cookie, "test") > -1));
      } catch (e) {
        $rootScope.$broadcast('LocalStorageModule.notification.error',e.message);
        return false;
      }
    };

    // Directly adds a value to cookies
    // Typically used as a fallback is local storage is not available in the browser
    // Example use: localStorageService.cookie.add('library','angular');
    var addToCookies = function (key, value) {

      if (typeof value == "undefined") return false;

      if (!browserSupportsCookies()) {
        $rootScope.$broadcast('LocalStorageModule.notification.error','COOKIES_NOT_SUPPORTED');
        return false;
      }

      try {
        var expiry = '', expiryDate = new Date();
        if (value === null) {
          cookie.expiry = -1;
          value = '';
        }
        if (cookie.expiry !== 0) {
          expiryDate.setTime(expiryDate.getTime() + (cookie.expiry*24*60*60*1000));
          expiry = ", expires="+expiryDate.toGMTString();
        }
        if (!!key) {
          document.cookie = prefix + key + "=" + encodeURIComponent(value) + expiry + ", path="+cookie.path;
        }
      } catch (e) {
        $rootScope.$broadcast('LocalStorageModule.notification.error',e.message);
        return false;
      }
      return true;
    };

    // Directly get a value from a cookie
    // Example use: localStorageService.cookie.get('library'); // returns 'angular'
    var getFromCookies = function (key) {
      if (!browserSupportsCookies()) {
        $rootScope.$broadcast('LocalStorageModule.notification.error','COOKIES_NOT_SUPPORTED');
        return false;
      }

      var cookies = document.cookie.split(',');
      for(var i=0;i < cookies.length;i++) {
        var thisCookie = cookies[i];
        while (thisCookie.charAt(0)==' ') {
          thisCookie = thisCookie.substring(1,thisCookie.length);
        }
        if (thisCookie.indexOf(prefix+key+'=') === 0) {
          return decodeURIComponent(thisCookie.substring(prefix.length+key.length+1,thisCookie.length));
        }
      }
      return null;
    };

    var removeFromCookies = function (key) {
      addToCookies(key,null);
    };

    var clearAllFromCookies = function () {
      var thisCookie = null, thisKey = null;
      var prefixLength = prefix.length;
      var cookies = document.cookie.split(';');
      for(var i=0;i < cookies.length;i++) {
        thisCookie = cookies[i];
        while (thisCookie.charAt(0)==' ') {
          thisCookie = thisCookie.substring(1,thisCookie.length);
        }
        key = thisCookie.substring(prefixLength,thisCookie.indexOf('='));
        removeFromCookies(key);
      }
    };

    // JSON stringify functions based on https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/JSON
    var stringifyJson = function (vContent, isJSON) {
      // If this is only a string and not a string in a recursive run of an object then let's return the string unadulterated
      if (typeof vContent === "string" && vContent.charAt(0) !== "{" && !isJSON) {
        return vContent;
      }
      if (vContent instanceof Object) {
        var sOutput = "";
        if (vContent.constructor === Array) {
          for (var nId = 0; nId < vContent.length; sOutput += this.stringifyJson(vContent[nId], true) + ",", nId++);
          return "[" + sOutput.substr(0, sOutput.length - 1) + "]";
        }
        if (vContent.toString !== Object.prototype.toString) { return "\"" + vContent.toString().replace(/"/g, "\\$&") + "\""; }
        for (var sProp in vContent) { sOutput += "\"" + sProp.replace(/"/g, "\\$&") + "\":" + this.stringifyJson(vContent[sProp], true) + ","; }
        return "{" + sOutput.substr(0, sOutput.length - 1) + "}";
      }
      return typeof vContent === "string" ? "\"" + vContent.replace(/"/g, "\\$&") + "\"" : String(vContent);
    };

    var parseJson = function (sJSON) {
      if (sJSON.charAt(0)!=='{') {
        return sJSON;
      }
      return eval("(" + sJSON + ")");
    };

    return {
      isSupported: browserSupportsLocalStorage,
      add: addToLocalStorage,
      get: getFromLocalStorage,
      remove: removeFromLocalStorage,
      clearAll: clearAllFromLocalStorage,
      stringifyJson: stringifyJson,
      parseJson: parseJson,
      cookie: {
        add: addToCookies,
        get: getFromCookies,
        remove: removeFromCookies,
        clearAll: clearAllFromCookies
      }
    };

  }];

  Console.groupEnd();
  return service;
});