How to Build SPAs With Angular Lazy Loading Modules

Building Single Page Applications (SPAs) with Angular can significantly enhance the user experience by making web applications faster and more responsive. One of the most effective techniques to optimize these applications is through the use of lazy loading modules. Lazy loading allows you to load parts of your application only when they are needed, which improves initial load times and reduces the amount of code that is initially loaded. In this article, we will explore how to implement lazy loading modules in Angular.

Understanding Lazy Loading in Angular

Lazy loading in Angular refers to the practice of loading modules on-demand rather than loading all at once when the application starts. This allows Angular to load only the necessary parts of your application, thus improving performance and scalability. When the user navigates to a particular route that requires a specific module, Angular loads that module at that moment.

Setting Up Angular Application

Before implementing lazy loading, ensure you have an Angular application set up. You can create a new Angular app using the Angular CLI:

ng new lazy-loading-demo

Navigate into your application folder:

cd lazy-loading-demo

Creating a Lazy Loaded Module

To create a lazy loaded module, use the Angular CLI to generate a new module:

ng generate module feature --route feature --module app.module

In this command, 'feature' is the name of the module, and by specifying the --route option, Angular automatically sets up lazy loading for this module.

Configuring Routing for Lazy Loading

Once the module is created, navigate to the routing file, usually named app-routing.module.ts. Here, you'll see that Angular has already set up a route for your new module:


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

This code snippet defines a route that points to your lazy-loaded module. When a user navigates to '/feature', Angular will load FeatureModule dynamically.

Creating Components Inside the Lazy Loaded Module

Next, generate a component within your lazy loaded module:

ng generate component feature/feature-component

Your component should now reside in the new module directory feature/feature-component. Ensure this component is declared within the feature.module.ts file:


@NgModule({
  declarations: [FeatureComponent],
  imports: [
    CommonModule,
    FeatureRoutingModule
  ]
})
export class FeatureModule { }

Setting Up Module Routing

Inside the lazy loaded feature-routing.module.ts, define the internal routes for your lazy loaded module:


const routes: Routes = [
  { path: '', component: FeatureComponent }
];

With this setup, when users access the '/feature' path, they’ll see the FeatureComponent.

Testing Lazy Loading

To test your lazy loaded module, run the application:

ng serve

Open your browser and navigate to http://localhost:4200/feature. You should see the content of your FeatureComponent.

Benefits of Lazy Loading

Implementing lazy loading in your Angular SPAs provides several advantages:

Improved Performance: Decreases loading time by only loading necessary modules.
Better User Experience: Users can interact with parts of the application faster.
Scalability: As your application grows, lazy loading ensures better management of resources.

Conclusion

Lazy loading modules in Angular is a powerful technique to enhance the performance of your Single Page Applications. By following the steps outlined in this article, you can create a more efficient and faster application, ensuring a seamless user experience. Implement lazy loading today and take your Angular application to the next level!

How to Build SPAs With Angular Lazy Loading Modules