javascript - angularjs and localStorage change event

Question

I store some data in the localStorage

what I want in my angularjs app is that when the data in the localStorage changed, the app rerender the app, how can I do this?

Answer 1

There is an angular localStorage module:

https://github.com/grevory/angular-local-storage

var DemoCtrl = function($scope, localStorageService) {

  localStorageService.clearAll();

  $scope.$watch('localStorageDemo', function(value){
    localStorageService.add('localStorageDemo',value);
    $scope.localStorageDemoValue = localStorageService.get('localStorageDemo');
  });

  $scope.storageType = 'Local storage';

  if (!localStorageService.isSupported()) {
    $scope.storageType = 'Cookie';
  }

};

After further thought you may need to change the module to broadcast on setItem so that you can get notified if the localStorage has been changed. Maybe fork and around line 50:

localStorage.setItem(prefix+key, value);
$rootScope.$broadcast('LocalStorageModule.notification.setItem',{key: prefix+key, newvalue: value});  // you could broadcast the old value if you want

or in the recent version of the library the casing was changed

$rootScope.$broadcast('LocalStorageModule.notification.setitem',{key: prefix+key, newvalue: value}); 

Then in your controller you can:

$scope.$on('LocalStorageModule.notification.setItem', function(event, parameters) {
   parameters.key;  // contains the key that changed
   parameters.newvalue;  // contains the new value
});

Here is a demo of the 2nd option: Demo: http://beta.plnkr.co/lpAm6SZdm2oRBm4LoIi1

** Updated **

I forked that project and have included the notifications here in the event you want to use this project: https://github.com/sbosell/angular-local-storage/blob/master/localStorageModule.js

I believe the original library accepted my PR. The reason I like this library is that it has a cookie backup in case the browser doesn't support local storage.