Refreshing the page causes the Angular/Ionic Singleton instance to be destroyed

I have a TypeScript singleton class that is responsible for storing the login credentials of a user. When I set these credentials on the login page and navigate to the next page using Angular Router.navigate (without passing any parameters), everything works perfectly fine. However, if I refresh the page, the singleton becomes undefined. How can I rectify this issue?

Here is the error message that appears after refreshing:

  • core.js:5980 ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'socialSecurityNumber' of undefined TypeError: Cannot read property 'socialSecurityNumber' of undefined

Thank you.

Answer №1

Whenever you hit the refresh button (F5 in the browser), the entire SPA is reloaded from scratch, including the creation of services.

This means that any new instance of a service will not have access to user data unless it's stored in local storage or cookies.

Make sure that the service is provided "in root" and not within any module providers array to avoid creating duplicate instances.

Answer №2

In situations like this, it is common practice to store the user's login details in browser storages or cookies.

Consider using Browser storages to save user-related information when working with service classes.

Learn more about browser storages and how they can be configured here.

  • Implementing browser storage in an Angular application

Once you have implemented the above steps, check the user credentials when the app component loads. Proceed as normal if credentials are found, otherwise redirect to the login page.

P.S: Some design changes may be necessary to decide whether users should continue with their current session or be redirected to the login page for a new session.

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