How to Implement Lazy Loading Routes in Angular SPAs

Lazy loading is a powerful technique in Angular applications that can significantly enhance performance by loading parts of the application only when needed. This is particularly beneficial for Single Page Applications (SPAs), where keeping the initial load time minimal is crucial. In this article, we will discuss how to implement lazy loading routes in Angular SPAs.

Understanding Lazy Loading in Angular

Lazy loading allows you to load feature modules only when the user navigates to a certain route. This means that rather than loading the entire application upfront, you can optimize the experience by fetching resources as they are required. This not only speeds up load times but also improves performance and user experience.

Setting Up an Angular Project

To get started, ensure you have an Angular project set up. You can create a new Angular application using Angular CLI with the following command:

ng new my-angular-app

Once your application is up and running, navigate to the project directory:

cd my-angular-app

Creating Feature Modules

Next, create the feature modules that will be lazily loaded. For example, let’s say we want to create a 'products' module. You can do this by running:

ng generate module products --route products --module app.module

This command will create a new module and set up a route for it automatically.

Setting Up Routing for Lazy Loading

To implement lazy loading, you need to adjust the routes in your app's routing module. Open your `app-routing.module.ts` file and set up the route for lazy loading:

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
const routes: Routes = [
  {
    path: 'products',
    loadChildren: () => import('./products/products.module').then(m => m.ProductsModule)
  },
  { path: '', redirectTo: '/home', pathMatch: 'full' },
];
@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

In the example above, the `loadChildren` property is set to a dynamic import of the `ProductsModule`. This ensures that the module is loaded only when the user navigates to the `/products` route.

Creating Components in Feature Modules

Once your feature module is set up, you can add components to it. For example, you can create a 'ProductsList' component:

ng generate component products/products-list

Update the `products-routing.module.ts` to include routes within the products module:

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { ProductsListComponent } from './products-list/products-list.component';
const routes: Routes = [
  { path: '', component: ProductsListComponent },
];
@NgModule({
  imports: [RouterModule.forChild(routes)],
  exports: [RouterModule]
})
export class ProductsRoutingModule { }

Configuring the Main App Module

Ensure your main app module includes the `AppRoutingModule`. Open `app.module.ts` and verify the imports:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Running and Testing Your Angular App

With everything set up, you can now run your Angular application:

ng serve

Navigate to `http://localhost:4200/` in your web browser. When you go to `http://localhost:4200/products`, the products module should be loaded asynchronously.

Conclusion

Implementing lazy loading in Angular SPAs is a straightforward process that can greatly enhance your application's performance. By loading feature modules on demand, users enjoy a faster and more

How to Implement Lazy Loading Routes in Angular SPAs