Angular Performance Tuning from the International JavaScript Conference 2017 in Munich

Slides from my Talk

Transcript

1. Through the Sound Barrier High-Performance Applications with Angular Manfred Steyer SOFTWAREarchitekt.at
2. About me… • Manfred Steyer • SOFTWAREarchitekt.at • Trainer & Consultant • Focus: Angular • Google Developer Expert (GDE) Page ▪ 3 Manfred Steyer
3. Turbo Button
4. Quick Wins Bundling Minification enableProdMode()
5. Contents • Lazy Loading and Preloading • Performance for Data Binding with OnPush • AOT and Tree Shaking • Caching with Service Worker
6. Lazy Loading
7. Module Structure Page ▪ 9 AppModule … … … SharedModule Root Module Feature Modules Shared Module
8. Lazy Loading Page ▪ 10 AppModule … … … SharedModule Root Module Feature Modules Shared Module
9. Root Module with Lazy Loading Page ▪ 11 const APP_ROUTE_CONFIG: Routes = [ { path: 'home', component: HomeComponent }, { path: 'flights', loadChildren: './[…]flight-booking.module#FlightBookingModule' } ];
10. Routes for "lazy" Module Page ▪ 12 const FLIGHT_ROUTES = [ { path: '', component: FlightBookingComponent, […] }, […] }
11. Routes for "lazy" Module Page ▪ 13 const FLIGHT_ROUTES = [ { path: 'subroute', component: FlightBookingComponent, […] }, […] } flight-booking/subroute Triggers Lazy Loading w/ loadChildren
12. DEMO
13. Lazy Loading • Lazy Loading means: Loading it later • Better startup performance • Delay during execution for loading on demand
14. Preloading
15. Idea • Module that might be needed later are loaded after the application started • When module is needed it is available immediately Page ▪ 17
16. Activate Preloading Page ▪ 18 … imports: [ […] RouterModule.forRoot( ROUTE_CONFIG, { preloadingStrategy: PreloadAllModules }); ] …
17. Performance- Tuning with OnPush
18. DEMO
19. OnPush flights flight flight {{ flight.id }} {{ flight.id }} FlightSearch Card Card Angular just checks when “notified”
20. "Notify" about change? • Change bound data (@Input) • OnPush: Angular just compares the object reference! • e. g. oldFlight === newFlight • Raise Event within the component • Notify a bound observable • Trigger it manually • Don't do this at home ;-) • At least: Try to avoid this
21. Activate OnPush @Component({ […] changeDetection: ChangeDetectionStrategy.OnPush }) export class FlightCard { […] @Input() flight; }
22. Change Inputs flights flight flight {{ flight.id }} {{ flight.id }} FlightSearch Card Card flightold === flightnew
23. Observables and OnPush <flight-card [item]="flight$ | async" […]> </flight-card>
24. DEMO
25. Ahead of Time (AOT) Compilation
26. Angular Compiler HTML Template JavaScript Template Compiler
27. Approaches • JIT: Just in Time, at runtime • AOT: Ahead of Time, during build
28. Advantages of AOT • Better Startup-Performance • Smaller Bundles: You don't need to include the compiler! • Tools can easier analyse the code • Remove not needed parts of frameworks • Tree Shaking
29. Angular CLI • ng build --prod • @ngtools/webpack with AotPlugin • Soon AngularCompilerPlugin • Can be used without CLI too
30. DEMO
31. Tree Shaking
32. Challenges • Most tree shaking tools are conservative • They just remove code when they are 100% sure • Very often, they aren't sure :-) • Solution: Angular Build Optimizer • Rewrites compiled code • Currently: Experimental
33. Sample Application w/ Angular Material
34. RxJS is huge
35. RxJS • We don't need every operator/ method • But: Methods are not tree-shakable for CLI/ webpack and others • Solution: Just import methods you need • Imports are patching Observable
36. Import Operators this.http.get<Flight>(url) .filter(f => f.price < 300) .map(f => toFlightOffer(f)) .subscribe(…); import 'rxjs'; // Import all --> Bad!
37. Import Operators import 'rxjs/add/operator/map'; // Patch Observable --> add map import 'rxjs/add/operator/filter'; this.http.get<Flight>(url) .filter(f => f.price < 300) .map(f => toFlightOffer(f)) .subscribe(…);
38. Better Alternative: Lettable Operators this.http.get<Flight>(url) .pipe( filter(f => f.price < 300), map(f => toFlightOffer(f)) ) .subscribe(…); import { map, filter } 'rxjs/operators';
39. Removing Whitespaces
40. Removing Whitespaces <p> Hello</p> <p>World! </p>
41. Removing Whitespaces <p> Hello</p> <p>World! </p> \n //Pseudo Code createNode('p', ' Hello World'); createNode('TEXT-NODE', '\n'); createNode('p', 'World!'); Template Compiler
42. Removing Whitespaces <p> Hello</p> <p>World! </p> \n //Pseudo Code createNode('p', ' Hello World'); createNode('TEXT-NODE', '\n'); createNode('p', 'World!'); Template Compiler
43. Removing Whitespaces @Component({ selector: 'flight-card', templateUrl: './flight-card.component.html', styleUrls: ['./flight-card.component.css'], preserveWhitespaces: false }) export class FlightCardComponent { […] }
44. Caching with Service Worker
45. What are Service Workers? • Background Tasks • Web App installs them • Are activated and deactivated on demand
46. Service Worker und Caching/ Offline • Intercept requests • Decide how to respond (Cache, Network) • Same Origin Policy • Caching Patterns • Cache only • Network only • Try cache first, then network • Try network first, then cache • etc.
47. Angular 5: ServiceWorkerModule
48. Service Worker with Workbox (sw.js) importScripts('./assets/workbox-sw.js'); const workboxSW = new WorkboxSW();
49. Service Worker with Workbox (sw.js) importScripts('./assets/workbox-sw.js'); const workboxSW = new WorkboxSW(); const networkFirst = workboxSW.strategies.networkFirst(); const cacheFirst = workboxSW.strategies.cacheFirst();
50. Service Worker with Workbox (sw.js) importScripts('./assets/workbox-sw.js'); const workboxSW = new WorkboxSW(); const networkFirst = workboxSW.strategies.networkFirst(); const cacheFirst = workboxSW.strategies.cacheFirst(); workboxSW.router.registerRoute( new RegExp('^http:\/\/www.angular.at\/api\/'), networkFirst); workboxSW.router.registerRoute(/./, cacheFirst);
51. DEMO
52. Server Side Rendering
53. Why Server Side Rendering? Prerender 1st Page Start up performance Consumer
54. renderModuleFactory […] renderModuleFactory(moduleFactory, { document: indexFileContentsAsString, url: options.req.url }) .then(string => { […] }); […] Available since Angular 4.0
55. DEMO
56. Challenges Other conditions Separate Services for Server and Client-Seite Renderer abstracts DOM 3rd parts libs Angular 5: Server Side DOM Simulation (partly)
57. More about this in my Medium Account • Configuration Details, Samples etc. • https://medium.com/@ManfredSteyer/angular-performance-tuning- article-series-6e3c33707b25
58. Conclusion Quick Wins Lazy Loading and Preloading OnPush w/ Immutables and Observables AOT and Tree Shaking Caching w/ Service Worker
59. Contact and Downloads [mail] manfred.steyer@SOFTWAREarchitekt.at [blog] SOFTWAREarchitekt.at [twitter] ManfredSteyer