如何在ngrx/effect (redux-observable)中分派多个动作？

import { Injectable } from '@angular/core';
import { Actions, createEffect, ofType } from '@ngrx/effects';
import { of } from 'rxjs';
import { mergeMap, map } from 'rxjs/operators';
import { Store } from '@ngrx/store';
import { someAction, anotherAction } from './actions';

@Injectable()
export class MyEffects {
  constructor(
    private actions$: Actions,
    private store: Store
  ) {}

  myEffect$ = createEffect(() =>
    this.actions$.pipe(
      ofType('[My Component] Do Something'),
      mergeMap(() => [
        store.dispatch(someAction()),
        store.dispatch(anotherAction())
      ])
    )
  );
}

import { Injectable } from '@angular/core';
import { Actions, createEffect, ofType } from '@ngrx/effects';
import { of } from 'rxjs';
import { switchMap, map } from 'rxjs/operators';
import { Store } from '@ngrx/store';
import { someAction, anotherAction } from './actions';

@Injectable()
export class MyEffects {
  constructor(
    private actions$: Actions,
    private store: Store
  ) {}

  myEffect$ = createEffect(() =>
    this.actions$.pipe(
      ofType('[My Component] Do Something'),
      switchMap(() => [
        store.dispatch(someAction()),
        store.dispatch(anotherAction())
      ])
    )
  );
}

import { Injectable } from '@angular/core';
import { Actions, createEffect, ofType } from '@ngrx/effects';
import { of } from 'rxjs';
import { exhaustMap, map } from 'rxjs/operators';
import { Store } from '@ngrx/store';
import { someAction, anotherAction } from './actions';

@Injectable()
export class MyEffects {
  constructor(
    private actions$: Actions,
    private store: Store
  ) {}

  myEffect$ = createEffect(() =>
    this.actions$.pipe(
      ofType('[My Component] Do Something'),
      exhaustMap(() => [
        store.dispatch(someAction()),
        store.dispatch(anotherAction())
      ])
    )
  );
}