Redux Refactoring Patterns with @ngrx/platform

Transcript

1. Redux Refactoring Patterns @GregOnNet co-IT.eu GmbH We Empower Outstanding Business Solutions
2. MY FRIEND OSCAR Meet Oscar 1. My Colleage 2. He works with 3. Passionated about Software Development
3. MY FRIEND OSCAR Meet Oscar 1. …He is not an early morning person.
4. Your Code Should Always Feel Like Home.
5. @GregOnNet Gregor Woiwode CTO
6. co-IT.eu GmbH We Empower Outstanding Business Solutions “ Collect your questions for the Q&A session, please. @GregOnNet
7. AGENDA Our Review With Oscar 1. Property Pattern 2. @ngrx/entity 3. @ngrx/router-store 4. selectors 5. ngrx-data
8. export function reducer(state = initialState, action: NotesActions): State { switch (action.type) { case NotesActionTypes.CreateNoteSuccess: { return { ...state, notes: [...state.notes, action.payload], loaded: true, loading: false } } case NotesActionTypes.LoadNotesSuccess: { return { ...state, notes: ...action.payload, loaded: true, loading: false } /* ... */ Redundant Code
9. export function reducer(state = initialState, action: NotesActions): State { switch (action.type) { case NotesActionTypes.CreateNoteSuccess: { return { ...state, notes: [...state.notes, action.payload], loaded: true, loading: false } } case NotesActionTypes.LoadNotesSuccess: { return { ...state, notes: ...action.payload, loaded: true, loading: false } /* ... */ Redundant Code
10. /* ... */ case NotesActionTypes.LoadAdditionalNotesSuccess: { return { ...state, notes: [...state.notes, ...action.payload], loaded: true, loading: false } } case NotesActionTypes.DeleteSingleNoteSuccess: { return { ...state, notes: state.notes.filter(note => note.guid !== action.payload.guid), loaded: true, loading: false } } /* ... */ Remove By Filtering
11. OSCAR‘S PROBLEM Large Switch-Case-Statements 1. Lot‘s of list operations we may not need every time 2. Hard to maintain 3. Less readable
12. Property Pattern SIMPLIFY STATE MUTATIONS
13. PROPERTY PATTERN Convert Collections To Dictionaries export interface State { notes: Note[]; } export interface State { notes: { [key: string]: Note }; } List to Object
14. PROPERTY PATTERN Delete Single Object return { ...state, notes: state.notes.filter(note => note.guid !== action.payload.guid ) } const { [action.payload.guid]: deleted, ...withoutDeleted } = state.notes; return { ...state, notes: withoutDeleted, }
15. MY FRIEND OSCAR Oscar asks… Maybe accessing data is more efficient. But the code complexity has increased. How can we benefit from this approach?
16. PROPERTY PATTERN Review Less Collection Operations More Performant Operations Less Readable Code
17. @ngrx/entity SIMPLIFY REDUCERS
18. @ngrx/entity Entity State export interface State extends EntityState<Note> {} export interface State<T> { ids: string[]; entities: { [id: string]: T }; } Leverages Property Pattern
19. @ngrx/entity Entity Adapter import { createEntityAdapter } from '@ngrx/entity'; const adapter = createEntityAdapter<T>(); The mighty helper
20. @ngrx/entity Entity Mutators Operations for single objects and collections
21. @ngrx/entity Simplify Mutations return adapter.removeOne( action.payload, state ); const { [action.payload.guid]: deleted, ...withoutDeleted } = state.notes; return { ...state, notes: withoutDeleted, } 1. Enusres Immutability 2. Applies State Mutation
22. @ngrx/entity Entity Selectors const adapter = createEntityAdapter<T>(); export const { selectAll, selectEntities, selectIds, selectTotal } = adapter.getSelectors();
23. @ngrx/entity Use Entity Selectors export class NotesDashboardComponent { notes$: Observable<Note[]>; constructor(private store: Store<fromNotes.State>) { this.notes$ = this.store.pipe(select(fromNotes.selectAll)); } }
24. Demo ENTITY ADAPTER
25. PROPERTY PATTERN Review Less Code Duplication Reusable Mutators & Selectors
26. MY FRIEND OSCAR Oscar asks… @ngrx/entity is nice, thanks. Can we tidy up these Switch-Case-Statements now?
27. createReducer SIMPLIFY REDUCER INFRASTRUCTURE
28. CREATE REDUCER Switch-Case-Anatomy Infrastructure UI-Logic case: a case: b case: …
29. CREATE REDUCER Factory Pattern To The Rescue const mutators: ActionHandlers<State> = { [NotesActionTypes.CreateNote]: notes.addOne, [NotesActionTypes.LoadNotesSuccessful]: notes.addMany }; export function reducer(state = initialState, action) { return createReducer<State>(mutators)(state, action); } Refer to last slide for the source
30. Demo REMOVE SWITCH-CASE-STATEMENTS
31. PROPERTY PATTERN Review Reduced Infrastructure Code Reducers do not need to be enhanced as Requirements change
32. MY FRIEND OSCAR Oscar asks… Small things can have a great impact to quality. But wait since you are here…
33. OSCAR‘S PROBLEM He thinks he breakse the Redux Pattern Shouldn’t the store be able to answer every question of a Component?
34. SINGLE SOURCE OF TRUTH How to deal with location state? /* ... */ export class NoteDetailsComponent { note$: Observable<Note>; constructor( private route: ActivatedRoute, private store: Store<fromNotes.State>) { this.note$ = this.route.params.pipe( switchMap(params => this.store.pipe(state => state.notes.entities[params.guid]) ) ); } }
35. @ngrx/router-store SIMPLIFY LOCATION STATE HANDLING
36. @ngrx/router-store Setup import { StoreRouterConnectingModule } from '@ngrx/router-store'; @NgModule({ imports: [ /* ... */ StoreRouterConnectingModule, ] /* ... */ }) export class AppModule {}
37. @ngrx/router-store Types & Reducer Come For Free import * as fromRouter from '@ngrx/router-store'; export interface State { routerReducer: fromRouter.RouterReducerState<RouterStateUrl>; } export const reducers: ActionReducerMap<State> = { routerReducer: fromRouter.routerReducer };
38. @ngrx/router-store Enhance The State Tree Store Notes Router State provided by @ngrx/router-store
39. @ngrx/router-store Access The Router State import { createFeatureSelector } from '@ngrx/store'; export const getRouterState = createFeatureSelector('routerReducer');
40. @ngrx/router-store Read Router State export const currentDetails = createSelector( getEntities, getRouterState, (notes, router) => entities[router.state.params.guid] ); RoutingComponent select
41. @ngrx/router-store The Reducer‘s Outcome Let’s traverse through the whole state tree! Of Cause Not!
42. Demo COMPRESS ROUTER STATE
43. PROPERTY PATTERN Review Store is Single Source of Truth again Reduced Complexity of Component Component does not rely on ActivatedRoute anymore
44. MY FRIEND OSCAR Oscar asks… This feels more correct than before, thanks. Wait! There is one very last thing…
45. OSCAR‘S PROBLEM I Can See A Revenent Pattern…. We only do CRUD operations. Do we need to repeat ourselves for every entity?
46. “ I see reccurring patterns…
47. Looking for the right answer…
48. ngrx-data SIMPLIFY STORE USING CONVENTIONS
49. Know, Can Do… Put Your Know-How Into Action!
50. ngrx-data Overview Actions Reducers Effects Data Services Dynamically sets up…
51. Configure an entity export const entityMetadata: EntityMetadataMap = { Note: { selectId: (note: Note) => note.guid } }; export const pluralNames = { Note: 'Notes' }; ngrx-data
52. Setup Entity Cache ngrx-data NgrxDataModule.forRoot({ entityMetadata, pluralNames }),
53. ngrx-data Data Services import { Note } from '../../models/note'; @Injectable() export class NotesBoard extends EntityCollectionServiceBase<Note> { constructor(entityServiceFactory: EntityCollectionServiceFactory) { super('Note', entityServiceFactory); } }
54. Convention Based Data Services ngrx-data localhost:4200/api/notes/<id> root entityName parameters
55. ngrx-data Built-In Functions Of A Data Service Mutators & Selectors for the given entity.
56. Demo CONFIGURE NGRX-DATA
57. ngrx-data Get Rid Of Unneeded Files Delete Delete Custom Configuration
58. PROPERTY PATTERN Review Less Files to maintain Scales good for many entities Highly Configurable Handles Loading State automatically High Learning Curve Lot‘s of things happen behind the scenes
59. co-IT.eu GmbH We Empower Outstanding Business Solutions Thank you! @GregOnNet e.co-it.eu/dwx18-gift e.co-it.eu/dwx18-ng
60. CREDITS Icons - from www.flaticon.com by Vectors Market - from www.flaticon.com by Freepik - from www.flaticon.com by Freepik