Implementing Deferred Loading of Components in Angular

Deferred loading, also known as lazy loading, is a crucial optimization technique for Angular applications. It involves loading components and modules only when they are needed, rather than loading everything upfront. This significantly improves initial load time and overall application performance, especially for large applications with many features.

Problem Description

Your task is to implement deferred loading for a specific feature module within an Angular application. The application has a main module and a separate "Admin" feature module. The "Admin" module contains a component called AdminDashboardComponent. The goal is to ensure that the AdminDashboardComponent and its associated module are only loaded when the user navigates to the /admin route.

What needs to be achieved:

1. Create a new Angular module named AdminModule.
2. Within AdminModule, create a component named AdminDashboardComponent.
3. Configure Angular's routing to lazy-load the AdminModule when the /admin route is accessed.
4. Ensure that the main application module does not load the AdminModule during initial application startup.

Key Requirements:

• The AdminModule should be loaded asynchronously.
• The AdminDashboardComponent should be accessible via the /admin route.
• The application should function correctly without the AdminModule initially loaded.
• The code should adhere to Angular best practices.

Expected Behavior:

• When the application initially loads, the AdminDashboardComponent and its module should not be loaded.
• When the user navigates to the /admin route, Angular should load the AdminModule in the background.
• Once the AdminModule is loaded, the AdminDashboardComponent should be displayed.
• Subsequent navigations to /admin should not trigger another module load (Angular's caching mechanism should handle this).

Edge Cases to Consider:

• What happens if the module load fails? (While not required to implement error handling in this challenge, consider it for a production application).
• How does this affect the overall application startup time?

Examples

Example 1:

Input: User navigates to the root route ('/').
Output: The application loads successfully, and the AdminDashboardComponent is not visible.
Explanation: The AdminModule is not loaded initially, so the AdminDashboardComponent is not rendered.

Example 2:

Input: User navigates to the '/admin' route.
Output: After a brief delay (due to module loading), the AdminDashboardComponent is displayed.
Explanation: Angular lazy-loads the AdminModule when the '/admin' route is accessed.

Example 3:

Input: User navigates from '/admin' to another route and then back to '/admin'.
Output: The AdminDashboardComponent is displayed immediately.
Explanation: Angular caches the AdminModule, so it doesn't need to be reloaded.

Constraints

• The solution must be written in TypeScript.
• The solution must use Angular's built-in routing and lazy loading features.
• The solution should be modular and well-structured.
• Assume a basic Angular project setup is already in place (e.g., ng new my-app). You don't need to create the entire project from scratch.
• Focus on the core lazy loading implementation; error handling and advanced features are not required for this challenge.

Notes

• Consider using the loadChildren property in your routing configuration to achieve lazy loading.
• The AdminModule should export the AdminDashboardComponent so it can be used in the routing configuration.
• Think about how to organize your files and folders within the AdminModule for clarity and maintainability.
• This challenge focuses on the implementation of lazy loading; you don't need to write extensive unit tests. However, ensure your code is testable.