Expert Tips for Optimizing Angular Performance and Productivity
Tags: angular
Published: 2023-06-01 23:20:01

## Expert Tips for Optimizing Angular Performance and Productivity



Are you an Angular developer looking to improve the performance and productivity of your web applications? Look no further. In this article, we will explore some expert tips and tricks for optimizing Angular performance and productivity.

### Tip #1: Use the OnPush Change Detection Strategy



Change detection is a fundamental part of Angular's architecture, responsible for detecting and updating component changes by comparing the current state of the component to the previous state. One of the most effective ways to optimize Angular performance is to use the OnPush change detection strategy. This technique triggers change detection only when a component input value changes, which can significantly improve the performance of your application.

To use the OnPush change detection strategy, you need to add the 'ChangeDetectionStrategy.OnPush' flag to your component's decorator as shown below:

<pre><code>@Component({
   changeDetection: ChangeDetectionStrategy.OnPush,
   selector: 'app-my-component',
   templateUrl: './my.component.html'
})
class MyComponent implements OnInit {
  ...
}
</code></pre>

By using this strategy, Angular will only trigger change detection when it's necessary, that is, when the input of the component changes. Additionally, OnPush change detection also helps reduce memory consumption and CPU cycles by preventing unnecessary checks of component properties and bindings, resulting in a faster and more optimized application.

### Tip #2: Leverage Angular's CLI



Angular's CLI (Command Line Interface) is a powerful tool that can help you boost your productivity and streamline your development workflow. The CLI provides a set of commands that make it easy to create, build, test, and deploy Angular applications. 

For example, the 'ng generate' command can automatically create a new component, directive, service, or module - with all the required files and folder structures - in just one line. Similarly, the 'ng build' command can build your application for production, optimize it, and create a deployable package in a single step.

In addition, the CLI provides a range of plugins and extensions that can enhance your development process. For instance, the 'ng lint' command can run a linter to check your code for errors and stylistic inconsistencies, while the 'ng test' command can launch a test suite and give you feedback on the results.

To get started with the CLI, simply install it with npm by running the following command:

<pre><code>npm install -g @angular/cli</code></pre>

Once installed, you can use the CLI commands directly from the terminal to create, build, test, and deploy your Angular application.

### Tip #3: Use Lazy Loading for Better Performance



Angular's lazy loading feature can significantly improve the performance of your application by loading only the necessary resources when they are required. For instance, if you combine lazy loading with the OnPush change detection strategy, you can dramatically reduce the number of requests your application makes - thereby improving the load time and user experience.

To use lazy loading in Angular, you need to create a separate module for each feature or part of your application, and then load that module dynamically when it's needed. Here's an example of how to implement lazy loading in Angular:

<pre><code>const routes: Routes = [
  {
    path: 'notifications',
    loadChildren: () => import('./notifications/notifications.module').then(m => m.NotificationsModule)
  }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }
</code></pre>

In the above example, we have defined a route to the 'notifications' feature module and loaded it lazily using the 'loadChildren' property of the route. This ensures that the 'notifications' module is only loaded when the user navigates to the '/notifications' URL, resulting in faster load times and better performance.

### Tip #4: Use Ahead-of-Time (AOT) Compilation



Angular provides two types of compilation: Just-in-Time (JIT) and Ahead-of-Time (AOT). JIT compilation compiles your Angular application in the browser at runtime, which can lead to slower load times and less efficient performance. On the other hand, AOT compilation pre-compiles your Angular application during the build phase, resulting in faster load times and better performance.

To use AOT compilation in your Angular application, you need to add the '--aot' flag to the 'ng build' or 'ng serve' commands. Here's an example of how to enable AOT compilation:

<pre><code>ng build --aot</code></pre>

Enabling AOT compilation can also help reduce the size of your application bundle, improve the startup time, and enable faster rendering of your application.

### Tip #5: Enable Production Mode



Angular's production mode is a feature that helps optimize your application by disabling certain debugging and development-specific features. This results in a more efficient and streamlined application that can run faster and consume fewer resources.

To enable production mode in your Angular application, simply set the 'enableProdMode()' flag in your main.ts file as shown below:

<pre><code>import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppModule } from './app/app.module';

enableProdMode();

platformBrowserDynamic().bootstrapModule(AppModule)
  .catch(err => console.log(err));</code></pre>

By enabling production mode, Angular will not run in the default development mode, which reduces memory consumption and CPU cycles, improves performance, and eliminates certain errors that may affect your application's performance.

### Tip #6: Use Custom Angular Directives and Pipes



Angular provides a range of built-in directives and pipes that can help you build robust and feature-rich applications. However, you can also create custom directives and pipes to enhance the functionality and performance of your application.

For instance, you may need to create a custom directive to perform a specific task or add a custom pipe to filter or transform data. By creating custom directives and pipes, you can simplify your code, reduce the number of component properties and methods, and improve your application's performance and maintainability.

Here's an example of a custom directive that changes the background color of an element based on the input value:

<pre><code>@Directive({
  selector: '[appHighlight]'
})
export class HighlightDirective {
  constructor(private elementRef: ElementRef) {}

  @Input('appHighlight') highlightColor: string;

  @HostListener('mouseenter') onMouseEnter() {
    this.highlight(this.highlightColor);
  }

  @HostListener('mouseleave') onMouseLeave() {
    this.highlight(null);
  }

  private highlight(color?: string) {
    this.elementRef.nativeElement.style.backgroundColor = color;
  }
}
</code></pre>

By using this custom 'HighlightDirective', you can add a highlight color to any HTML element by simply adding the 'appHighlight' attribute to the element and passing the desired color as an input.

### Wrapping Up



Angular is a powerful and versatile framework for building web applications, but optimizing its performance and productivity can be challenging. By using the expert tips and tricks outlined in this article, you can streamline your development workflow, improve your application's performance, and create faster, more efficient Angular applications.