Angular DI Processor Pattern

Implement Processor Pattern with Angular Dependency Injection

Transcript

1. Angular | Dependency Injection | Processor Pattern + +
2. @JecelynYeen From Kuala Lumpur, Malaysia • GDE - Web technologies, Angular • Software Architect @ Randstad Organizer:
3. • Dependency Injection (DI) • DI in Angular • Processor Pattern • DI + Processor Pattern in Angular + +
4. Dependency Injection . What & Why?
5. Weapon is made of material (wood). Ninja needs a weapon (nunchakus). We have a ninja.
6. - Single Responsibility - Tightly coupled - Hard to unit test
7. Dependency Injection
8. Hookup implementation during bootstrap inject in constructor no need to instantiate
9. Replace implementation under the hood
10. Dependency Injection • Unit testable • Reusability • Loosely coupled • Dependency Inversion principle
11. DI in Angular
12. service service hook up
13. • UseClass • UseValue • UseFactory • UseExisting + https://offering.solutions/blog/articles/2018/08/17/using-useclass-usefactory-usevalue- useexisting-with-treeshakable-providers-in-angular/ https://blog.thoughtram.io/angular/2015/05/18/dependency-injection-in-angular-2.html
14. Dependency Injection is static
15. Dependency Injection is static hook up only once
16. what if our ninja need to switch weapon dynamically https://di-processor.firebaseapp.com/ninja-di
17. what if our ninja need to switch weapon dynamically https://di-processor.firebaseapp.com/ninja-di nunchakus, dart, stick, sword
18. Processor Pattern using injection token & multi-provider
19. weapon interface name, draw(), animate() Inject into NinjaComponent as weapon[ ] injection token processors multi-providers
20. Injection Token + Processor Interface
21. Processor implement the interface
22. Multiple providers with same token one token multiple implementations set as multi
23. Inject multiple providers Injection 4 processors get one processor Invoke processor functions
24. Production Use Case: Chart Processors
25. - chart type - title / menu - processing logic - labels & tooltips Differences - they are all charts - same interface:- - processData() - name, title, etc Similar https://di-processor.firebaseapp.com
26. YYYY-MM what users want to see YYYY-MM-DD what backend returns Frontend developer
27. what your chart library wants what you need to do • transform data (loop & group it by year month) • sort it • generate chart configuration
28. What you actually do - Chart Processor https://github.com/chybie/di-processor/blob/master/src/app/chart-di/services/chart-new-starter-processor.service.ts private
29. Injection Token + Processor Interface
30. Multiple providers with same token
31. Dashboard Component
32. Other useful scenario • Data table processors • Search processors https://stackoverflow.com/questions/48382323/angular-lookup-all- providers-implementing-a-specific-interface/ 48383858#comment83773434_48383858
33. Benefits • Abstraction • Plugins
34. slides: https://speakerdeck.com/chybie/angular-di-processor-pattern demo: https://di-processor.firebaseapp.com code: https://github.com/chybie/di-processor code (inject by service): https://stackblitz.com/edit/ninja-weapon- processors?file=src%2Fapp%2Fninja%2Fninja.component.ts twitter: @JecelynYeen + +