Day 22 Challenge: Speed Up Your Angular Projects by 10x

The goal of this challenge is to guide developers through key strategies that will help optimize and speed up Angular applications, improving both development and production performance. By following the steps and best practices outlined, you'll be able to boost the performance of your Angular projects by 10x or more!

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Challenge Overview

Your challenge is to optimize your Angular project for performance by implementing various techniques that reduce build times, enhance runtime performance, and improve the user experience. You'll need to analyze your current project, apply optimizations, and measure the impact.

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Step 1: Analyze Your Current Angular Project

Before optimizing, understand where your application is currently standing in terms of performance.

1.1: Measure Build Time

• Run the build command and note the time taken.

    ng build --prod
  

1.2: Measure Load Time

• Open your app in the browser and use Chrome DevTools to analyze the page load time (Network Tab → Reload and observe). Take note of the Time to First Byte (TTFB) and First Contentful Paint (FCP).

1.3: Measure Runtime Performance

• Use Angular DevTools or Chrome Performance Tab to profile your app. Identify slow change detection cycles, expensive rendering operations, or any heavy computational tasks.

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Step 2: Apply Angular CLI Optimizations

2.1: Enable Ahead-of-Time (AOT) Compilation

• Make sure your app uses AOT compilation for production builds to optimize rendering.

    ng build --prod --aot
  

  Goal: Reduce runtime overhead and enhance startup speed.

2.2: Enable Lazy Loading

• Break your app into smaller modules and lazy-load them to decrease the initial load time.

  Modify the routes in your app-routing.module.ts:

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

  Goal: Load large modules only when needed to speed up initial loading.

2.3: Tree Shaking

• Ensure that unused code is removed during the build process. Angular does this by default in production mode, but you should verify by analyzing the bundle.

  Goal: Reduce the size of your JavaScript bundles.

2.4: Use Webpack Bundle Analyzer

• After building with the --prod flag, generate stats to analyze your bundle:

    ng build --prod --stats-json
  

  Then, use webpack-bundle-analyzer to find any unnecessary dependencies or oversized files.

  Goal: Identify and remove large, unused dependencies.

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Step 3: Optimize Change Detection

3.1: Use OnPush Change Detection Strategy

• Modify components to use ChangeDetectionStrategy.OnPush, which only triggers change detection when input properties change or when events are fired.

    @Component({
      selector: 'app-example',
      changeDetection: ChangeDetectionStrategy.OnPush,
      templateUrl: './example.component.html',
      styleUrls: ['./example.component.css']
    })
    export class ExampleComponent {
      @Input() data: any;
    }
  

  Goal: Minimize the number of checks Angular needs to perform.

3.2: Optimize Template Expressions

• Avoid complex logic in your templates. Move heavy logic into the component class to ensure the template only renders static values.

  Goal: Prevent repeated computations during rendering.

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Step 4: Implement Lazy Loading for Images and Assets

4.1: Lazy Load Images

• Use loading="lazy" in <img> tags to load images only when they enter the viewport.

    <img [src]="image.url" loading="lazy" />
  

  Goal: Improve initial page load times by deferring image loading.

4.2: Use SVGs Instead of PNGs/JPEGs

• Use SVG graphics where possible for smaller file sizes and better performance.

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Step 5: Profile Your Application

5.1: Use Angular DevTools

• Profile your app with Angular DevTools to identify areas where the app's performance can be improved. Look for:

  • Slow component re-renders

  • Inefficient change detection

  • Excessive HTTP requests

5.2: Use Chrome Performance Tab

• Record a performance trace using Chrome DevTools' Performance tab. Pay attention to:

  • JavaScript execution time

  • Layout and paint times

  • Network request times

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Step 6: Apply Best Practices for Production Builds

6.1: Enable Service Workers for Caching

• Add PWA support to your app to improve load times and offline performance.

    ng add @angular/pwa
  

  Goal: Cache assets and data to improve performance for returning users.

6.2: Minify and Compress Assets

• Ensure that CSS, JavaScript, and images are minified and compressed in production builds. Angular CLI does this automatically with --prod builds.

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Step 7: Evaluate Impact

7.1: Compare Build Time

• After implementing optimizations, run the build command again and compare the time taken:

    ng build --prod
  

7.2: Compare Load Time

• Revisit the Chrome DevTools and compare the load time (FCP and TTFB) before and after the optimizations.

7.3: Compare Runtime Performance

• Analyze the performance of the app using Angular DevTools or Chrome Performance Tab again. Look for reduced change detection cycles and fewer unnecessary re-renders.

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Step 8: Challenge Completion

8.1: Document Results

• Document the changes you made and the impact they had. Include:

  • Before and after build time

  • Before and after load time

  • Before and after runtime performance

8.2: Share Your Results

• Share your results with the community or your team to inspire others and see if they can take your optimizations even further.

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Challenge Outcome

By following the steps in this challenge, you should see a significant improvement in both development speed (via faster builds) and user experience (via faster load times and smoother interactions). A 10x improvement is possible if you combine multiple strategies, like lazy loading, tree shaking, and change detection optimization, with a focus on optimizing assets and dependencies.

Bonus: Try implementing server-side rendering (SSR) with Angular Universal for further performance gains!

Good luck, and happy optimizing! 🎯