Managing and Accessing Router State in Angular

Angular's router is a powerful tool for navigating between different views in an application. Beyond just changing URLs, it also provides mechanisms to manage and access data associated with specific routes. This challenge focuses on implementing and leveraging router state to pass complex data between components and to access it within those components.

Problem Description

Your task is to create an Angular application that demonstrates how to effectively manage and access router state. Specifically, you need to:

1. Navigate with State: Implement a mechanism to navigate to a specific route and pass complex data (e.g., an object) as part of the router state.
2. Access State in Destination Component: In the component that is activated by the route, retrieve and display the data passed via router state.
3. Handle Missing State: Ensure your destination component gracefully handles cases where no router state is provided.

This is crucial for scenarios where you need to pass information that doesn't fit neatly into URL parameters or query parameters, such as user preferences, temporary data, or complex configurations.

Examples

Example 1: Navigating and Displaying User Data

• Scenario: A user clicks a link to view details of a specific user.

• Input:

  • Component A (e.g., UserListComponent) has a list of users. Each user object has id, name, and email properties.
  • User clicks on a "View Details" button for a user with { id: 1, name: 'Alice', email: 'alice@example.com' }.

• Action: Navigate from Component A to a route configured for Component B (e.g., user-details/:id) and pass the entire user object in the router state.

• Output (in Component B, e.g., UserDetailsComponent): The component should display the user's name and email.

  User Details:
  Name: Alice
  Email: alice@example.com
  

• Explanation: Component A uses router.navigate with state: { user: { id: 1, name: 'Alice', email: 'alice@example.com' } } to navigate. Component B accesses history.state.user to retrieve and display the data.

Example 2: Handling Navigation without State

• Scenario: A user directly navigates to the user details page without coming from a list or having any specific user data pre-loaded.

• Input:

  • User directly navigates to the /user-details/2 route (assuming the route is configured to expect an ID, though it might not be used if state is prioritized).

• Action: The UserDetailsComponent is activated.

• Output (in UserDetailsComponent):

  • The component should display a message indicating that no user data was provided.

  No user data available.
  

• Explanation: When history.state is checked and history.state.user is undefined, the component renders a fallback message.

Constraints

• The application must be built using Angular version 14 or later.
• Solution must be written in TypeScript.
• The routing configuration should utilize RouterModule.forRoot() or RouterModule.forChild().
• You should primarily use the Router service from @angular/router for navigation.
• The data passed as state should be a JSON-serializable object.
• Performance is not a critical concern for this specific challenge, but inefficient or overly complex state management should be avoided.

Notes

• Consider using the ActivatedRoute service to access route information, but for state, you will directly interact with history.state from the browser's window.history object.
• The state property of history.state is where the data passed during navigation is stored.
• Think about how you would structure your components and routes to facilitate this state management.
• This challenge emphasizes passing data that isn't part of the URL.