How to enable lazy loading routes on Angular Routing

In Angular, routing enables navigation from one view to another as users perform application tasks. To use routing in an Angular application, you need to set up the routes, configure the router, and define a component to be displayed for each route.

Here is an example of how you can set up routing in an Angular application:

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';

import { HomeComponent } from './home/home.component';
import { AboutComponent } from './about/about.component';

const routes: Routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

In this example, the AppRoutingModule defines two routes: one for the root path ('') and one for the /about path. The HomeComponent will be displayed when the root path is visited, and the AboutComponent will be displayed when the /about path is visited.

To display the component for the active route, you can use the router-outlet directive in the template of the root component:

<router-outlet></router-outlet>

You can also use the RouterLink directive to create links to the different routes in your application:

<a routerLink="/about">About</a>

Lazy Loading Routes

Angular provides a feature called lazy loading to load routes only when they are needed. Lazy loading routes can improve the performance of your application by reducing the amount of code that needs to be loaded initially.

To use lazy loading in your Angular application, you can use the loadChildren property in the route configuration. The loadChildren property should be set to a function that returns a promise that resolves to the module that should be lazy loaded.

Here is an example of how you can use lazy loading in your Angular application:

const routes: Routes = [
  {
    path: 'lazy',
    loadChildren: () => import('./lazy/lazy.module').then(m => m.LazyModule)
  }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

In this example, the LazyModule will only be loaded when the /lazy route is visited. This can help improve the initial loading time of your application by only loading the code that is needed.

You can also use the data property of the route configuration to pass additional data to the lazy-loaded module. This can be useful if you need to pass some configuration or initialization data to the lazy-loaded module.

const routes: Routes = [
  {
    path: 'lazy',
    data: { title: 'Lazy Loaded Route' },
    loadChildren: () => import('./lazy/lazy.module').then(m => m.LazyModule)
  }
];

In the lazy-loaded module, you can access the data passed in the route configuration using the ActivatedRoute service.

constructor(private route: ActivatedRoute) {
  this.route.data.subscribe(data => {
    console.log(data.title);
  });
}

In Conclusion

Here are some best practices for using lazy loading and routing in Angular:

1. Use lazy loading for routes that are not critical to the initial rendering of the application. This can improve the initial loading time of your application by only loading the code that is needed.
2. Use the preload strategy to preload lazy-loaded routes in the background. This can improve the user experience by reducing the time it takes for the lazy-loaded route to be displayed when it is visited.
3. Use the data property of the route configuration to pass additional data to the lazy-loaded module. This can be useful if you need to pass some configuration or initialization data to the lazy-loaded module.
4. Use the canLoad guard to control when a route can be lazy-loaded. This can be useful if you need to check for certain conditions before allowing a route to be lazy-loaded.
5. Use the canActivate guard to control whether a route can be activated. This can be useful if you need to check for certain conditions before allowing a route to be displayed.
6. Use the resolve property of the route configuration to pre-fetch data for a route. This can improve the user experience by reducing the time it takes for the data to be displayed when the route is activated.
7. Use the RouterLinkActive directive to apply a CSS class to active router links. This can help improve the user experience by providing visual feedback when a link is active.

I hope these best practices help improve your use of lazy loading and routing in your Angular application. Let me know if you have any questions.