Angular Lazy Loading Module Implementation

This challenge focuses on implementing lazy loading for a feature module in an Angular application. Lazy loading is a crucial optimization technique that improves initial application load times by only loading modules when they are actually needed by the user. You will create a scenario where a specific feature, like a "User Management" section, is only loaded when the user navigates to its corresponding route.

Problem Description

Your task is to implement lazy loading for a new "User Management" feature within an existing Angular application. This feature should not be part of the initial bundle loaded by the application. Instead, it should be loaded on demand when the user navigates to a route designated for user management.

Key Requirements:

1. Create a Feature Module: Develop a new Angular module (UserManagementModule) that encapsulates all components, services, and other related artifacts for the user management feature.
2. Configure Lazy Loading: Modify the Angular Router configuration to define a route that lazily loads the UserManagementModule.
3. Create a Feature Component: Implement a simple component (UserListComponent) within the UserManagementModule that will be displayed when the lazy-loaded module is activated.
4. Implement Navigation: Add a link or button in the main application to navigate to the user management feature's route.

Expected Behavior:

• When the application initially loads, the UserManagementModule should NOT be downloaded or included in the main JavaScript bundle.
• When the user clicks the navigation link/button for "User Management," the UserManagementModule should be dynamically loaded.
• Once loaded, the UserListComponent should be displayed within the application's routing outlet.
• Subsequent navigations to the user management route should not re-load the module (if cached).

Edge Cases:

• Ensure the application gracefully handles scenarios where the lazy-loaded module might fail to load (though for this challenge, you don't need to implement explicit error handling for network failures, just ensure the configuration is correct).

Examples

Example 1: Application Structure

Let's assume a basic Angular project structure:

src/
├── app/
│   ├── app-routing.module.ts
│   ├── app.component.html
│   ├── app.component.ts
│   ├── app.module.ts
│   └── home/ (existing feature module, not lazy-loaded for this problem)
│       └── ...
├── assets/
├── environments/
├── index.html
├── main.ts
└── ...

Your task is to add:

src/
├── app/
│   ├── app-routing.module.ts  <-- Modified to include lazy loading
│   ├── app.component.html     <-- Modified to include navigation link
│   ├── app.component.ts
│   ├── app.module.ts
│   ├── home/
│   │   └── ...
│   └── user-management/       <-- New folder for the feature module
│       ├── user-list.component.html
│       ├── user-list.component.ts
│       ├── user-management-routing.module.ts  <-- New module for feature routing
│       └── user-management.module.ts          <-- New feature module
└── ...

Input:

• The initial app-routing.module.ts and app.component.html.
• The task of creating the user-management folder, user-management.module.ts, user-management-routing.module.ts, and user-list.component.ts.

Output:

• A working Angular application where clicking a "User Management" link triggers the lazy loading of the UserManagementModule and displays the UserListComponent.

Explanation:

1. user-management.module.ts: This module will declare UserListComponent and import necessary Angular modules (like CommonModule). It will NOT import AppRoutingModule.
2. user-management-routing.module.ts: This module will define routes specific to the user management feature, including the path for UserListComponent.
3. app-routing.module.ts: This file will be updated to include a route that uses loadChildren to point to the UserManagementModule and its routing module.
4. app.component.html: A link will be added to navigate to the route configured for user management.

Constraints

• The primary focus is on the correct implementation of Angular's loadChildren mechanism for routing.
• The UserListComponent can be extremely simple (e.g., just display a heading "User Management").
• No external libraries beyond Angular's core framework should be used for this challenge.
• The solution should be implemented in TypeScript.

Notes

• Remember that loadChildren expects a path to the module file and the module name, often in a specific format (e.g., './user-management/user-management.module#UserManagementModule'). Modern Angular versions often prefer using dynamic import() syntax.
• Consider how the UserManagementModule will declare its own routing using RouterModule.forChild().
• The main AppModule should not import UserManagementModule directly.
• Ensure your tsconfig.json has the correct module settings for dynamic imports if you choose that approach.