ngrx-correlation-id

A ngrx store library to track an asynchronous activity such as a http request, a ngrx effect or anything else.

Supports

• Angular 13 and ngrx/store@13
• Angular 12 and ngrx/store@12
• Angular 11 and ngrx/store@11
• Angular 10 and ngrx/store@10
• Angular 9 and ngrx/store@9
• Angular 8 and ngrx/store@8
• Angular 7 and ngrx/store@7
• Angular 6 and ngrx/store@6

API short list

Please check source code

• NgrxCorrelationIdModule

• CidTask

• cidTask(correlationId, Observable)
• cidWait()

• store.select(selectCid, correlationId)

• cidStart(correlationId: string)
• cidPayload(correlationId: string, payload: any)
• cidEnd(correlationId: string)
• cidRemove(correlationId: string)

How to use

Import NgrxCorrelationIdModule in the same module where you import StoreModule.forRoot.

import {NgrxCorrelationIdModule} from 'ngrx-correlation-id';

@NgModule({
    imports: [
        StoreModule.forRoot(/* ... */),
        NgrxCorrelationIdModule, // <- import it here
    ],
})
export class AppModule {}

Add cid: string to props of an action you want to track.

export const loadUsers = createAction(
  '[User] Load Users',
  props<{cid: string}>(), // <- correlation id
);

Wrap an effect pipe with cidTask. The first argument is a cid of the current task. The second argument is a stream that should be tracked.

Optionally you can dispatch cidPayload action with a custom payload. In this case we want our payload to be an array of ids of users.

import {cidPayload, cidTask} from 'ngrx-correlation-id';

@Injectable()
export class UsersEffects {
    @Effect()
    public readonly loadUsers$ = this.actions$.pipe(
        ofType(loadUsers),
        switchMap(({cid}) => cidTask(cid, this.http.get<Array<User>>('v2/api/users').pipe(
            switchMap(users => of(
                upsertUsers({items: users}),
                cidPayload({cid, payload: users.map(user => user.id)}),
            )),
        ))),
    );

    constructor(
        protected readonly actions$: Actions,
        private readonly http: HttpClient,
    ) {}
}

Update a component to use cid and all the features of the lib.

import {cidRemove, CidTask, cidWait, selectCid} from 'ngrx-correlation-id';

export class EntityComponent implements OnInit, OnDestroy {
    public readonly users$: Observable<Array<User>>;

    // set here an unique value to distinguish this task from others.
    private readonly cid: string = `randomString`;

    constructor(private readonly store: Store) {
        // selecting the related task that belongs to cid.
        this.users$ = this.store.select<CidTask<Array<string>>>(selectCid, this.cid).pipe(

            // doesn't emit until the task isn't completed
            cidWait(), // waits until the task starts, then waits until the task ends and the task.

            map(task => task.payload),
            withLatestFrom(this.store.select(selectUsers)),
            map(([ids, users]) => users && users.filter(user => ids.indexOf(user.id) !== -1) || []),
        );
    }

    public ngOnInit(): void {
        // dispatching an action to load users.
        this.store.dispatch(loadUsers({cid: this.cid}));
    }

    public ngOnDestroy(): void {
        // clearing payload and selector
        this.store.dispatch(cidRemove({cid: this.cid}));
        selectCid.release();
    }
}