Angular Modules and Lazy Loading

Angular Modules and Lazy Loading

1. Introduction to Angular Modules:

Angular modules are containers for a set of related components, services, directives, and pipes that define the functionality of an Angular application. They help in organizing the codebase and make it easier to manage the application's features.

2. Creating an Angular Module:

To create an Angular module, use the @NgModule decorator. It allows you to specify the components, services, and other modules that will be part of the module.

typescript
// app.module.ts

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FeatureComponent } from './feature/feature.component';
import { FeatureService } from './feature.service';

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

3. Lazy Loading in Angular:

Lazy loading is a technique in Angular that loads modules asynchronously when they are needed, instead of loading everything upfront. This helps in reducing the initial bundle size and improving application performance.

4. Implementing Lazy Loading:

To implement lazy loading, you need to create a separate module for the feature you want to load lazily. Then, you can use the loadChildren property in the RouterModule to specify the path to the module.

typescript
// app-routing.module.ts

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

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

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

5. Using Lazy Loaded Module:

With lazy loading implemented, you can now use the lazy-loaded module's components in your templates as usual.

html
<!-- app.component.html -->

<a routerLink="/lazy">Lazy Feature</a>
<router-outlet></router-outlet>

6. Practical Example:

Suppose we have a feature called "Lazy Feature" with its own components and services. By implementing lazy loading, we can load this feature only when the user navigates to the '/lazy' route, keeping the initial bundle smaller.

Explanation:

Lazy loading is beneficial when you have large modules or features that might not be used by all users immediately. By splitting your application into smaller chunks and loading them on-demand, you can achieve better performance and reduce initial loading time.

Remember that when using lazy loading, it's essential to optimize your routes and modules to ensure smooth user experiences and efficient resource utilization.