I have an object that contains some data that I need to load when my application starts. Once its loaded I need to be able to reuse in multiple places on my application.
What is the best way to do this?
Right now I have a factory that I inject into my controller and I pull the data, the problem is that I'm doing the data pull multiple times.
What would be the best way to pull the data only when I load the application?
I would only need to access the data on my templates and pull the correct Key Value from the object where I need.
You need to use an angularjs service instead of a factory. Services in angularjs are singleton where factories are not.
You should be able to just change how your factory is registered to make it a service instead.
var yourModule = angular.module('yourModule', []);
yourModule.service(
instead of
yourModule.factory(
more info here: https://docs.angularjs.org/guide/services
Related
I have an Angular js factory. In which I am storing the user information after successful login. Now I have multiple controllers in all of them I need this user information so I need to inject this factory to each and every controller. Is there any way to access this factory data throughout the project without injecting in each and every controller?
Can we directly inject it into the module?
Some suggestions :
storing the user information in factory is not a good approach because if user reload the page it will reset the factory data and user will not exist anymore.
As sajeetharan suggested, you can use HTML5 localStorage or sessionStorage to store the user information. So, that without injecting you can easily access stored storage value everywhere you want.
Yes, if you need the user information so you need to inject the factory to each and every controller because on switching from one controller to another controller you have to fetch the data from the factory.If you inject the factory only in the main module it will not load the factory when you move from success login to some other page.
User information can be stored in local storage or cookie so that i can be accessed anywhere.
You can also consider using $rootScope, in that case also you need to inject in all the modules which you require.
a factory is part of a module.
Injecting it into the controllers needed is the way of using the saved values throughout the module.
Have 2 pages for one long process. Both in one controller. My problem is:
In first page, using angular - run method that generate some data. Store that data in property in controller. Move to another page, using angular - run another method and that is... my data in property is null. Is there a solution to store data in controller properties in thid situation?
New instance of a controller is created on every request so whatever you save in property of your controller this will be destroyed together with a controller when request is ended. You have to store this data either on client(cookie, local storage) or server side (session, cache, database etc.).
With ASP.Net MVC, you can't store data in a property between 2 actions.
For achieving this, you have to use cache strategy.
Please, see this link.
So my understanding is that factories are singletons so any stateful data for a session would be ill placed here.
My next point of call was a service which returns a new instance of the service when injected however I am unsure how I would share one instance of the service to multiple controllers.
Is this an accepted way to solve this issue or does angular provide a better way?
My current use case is that I have a view with some partial views (each partial has it's own controller) and a modal window which takes in a row id and will display data dependant on that data.
I need to be able to share a instance of the service (or equivalent) across these controllers but on a per session basis.
How is this best done?
The singleton exists for one user and loaded SPA. Thats what you would usually refer to as a session. Its a good place to store data that needs to be accessed by different controllers.
In AngularJs is there any way to share object between two web pages without using $cookies. For example my Login page controller have different angular.module and my other controller have different angular.module but I need to share credentials between Login page and another page without using $cookies.
Between independent page
You can use the standard HTML5 sessionStorage and localStorage object
For simple synchronous storage access HTML 5 introduces the localStorage attribute on the Window object:
localStorage["status"] = "Idling.";
LocalStorage is like cookie, sessionStorage will be clean when closing your browser.
In angular
You can use a factory which is technically a singleton. But if you refresh your page, all JS will be re-initialize and you will lose your data. A Service is also possible.
Here is a link on an other topic explaining difference between Services and Factory : AngularJS: Service vs provider vs factory
To create Services/Factory, give a look at Angular official documentation, it is well explained.
Perfect mix
What you need to do is create a Service, and at each modification you stringify it to store on a local/session Storage. On load, when angular create your service, you look in your storage for initialization value and your object is back.
This is quite common for authentification for exemple. You store a token to keep authentification when refreshing ;). Let me know if any difficulty to implement.
Have you considered creating a Service which stores these login credentials? You could then use Dependency Injection to have this Service available in both controllers.
Sharing the information between different pages is a critical task which can be done with the help of Controllers.
In AngularJS, we can share the data between controllers in three ways:
Factory: Object is created inside the factory and return it .
Service: With the service, you just have a standard function that uses the this keyword to define function.
Provider: With the provider, there’s a $get you define and it can be used to get the object that returns the data.
I like that Durandal has Activate/Deactivate methods that get called on the VM and that the views can even be cached.
Is there a way to have this same features in Angular?
You can use a service / factory. These are singletons in AngularJS and you can inject them to the controller. Strictly have one service per controller and the service will be maintained between navigations to the view / controller.
http://docs.angularjs.org/guide/dev_guide.services.creating_services
The way this would work is that your controller would take myService as an injected dependency. Then you assign it to $scope as $scope.cache = myService. Then in your view you bind to cache.someProperty for elements that wanted cached.
Just as an aside:
You can even share services containing state data between controllers. Although I would recommend against this pattern, because it looks like global state. Services you share between controllers should ideally only provide functionality instead of being data objects. Unless you are specifically looking for a global data store :)