Making ngrx-effects REST call - html

Question

I am developing angular REST application using ngrx/effects, I am using example application GIT. I am trying to replace hardcoded json data in effects, from http REST end. I am getting errors "Effect "GetTodoEffects.todo$" dispatched an invalid action" . Could you please help me in solving it. Every thing is same as git code, except effects code which is i am pasting below.
Effects code:
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/mergeMap';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/debounceTime';
import 'rxjs/add/operator/withLatestFrom'
import { of } from 'rxjs/observable/of';
import { Injectable } from '#angular/core';
import { Observable } from 'rxjs/Observable';
import { Action, Store } from '#ngrx/store';
import { Actions, Effect, toPayload } from '#ngrx/effects';
import * as Act from '../actions/app.actions';
import * as fromStore from '../reducers';
import { HttpClient } from '#angular/common/http';
#Injectable()
export class GetTodoEffects {
#Effect() todo$ = this.actions$.ofType(Act.GET_TODO)
.map(toPayload)
.withLatestFrom(this.store$)
.mergeMap(([ payload, store ]) => {
return this.http$
.get(`http://localhost:4000/data/`)
.map(data => {
return [
new Act.GetTodoSuccess({ data: data })
]
})
.catch((error) => {
return [
new Act.GetTodoFailed({ error: error })
]
})
});
constructor(
private actions$: Actions,
private http$: HttpClient,
private store$: Store<fromStore.State>
) {}
}
I am using json-server as REST end point. json-server --port 4000 --watch expt-results-sample.json
expt-results-sample.json
[
{
text: "Todo 1"
},
{
text: "Todo 2"
},
{
text: "Todo 3"
}
]
})
]

Answer 1

First thing I suspect is the array. Try changing it to an observable.
return this.http$
.get(`http://localhost:4000/data/`)
.map(data => {
// You don't need an array because it's only 1 item
// If you want array use `Observable.from([ /* actions here */ ])`
// but then you'll need to change `map` above to
// `mergeMap` or `switchMap`
// (no big difference for this use case,
// `switchMap` is more conventional in Ngrx effects)
return new Act.GetTodoSuccess({ data: data });
})
.catch((error) => {
// You probably haven't called this yet,
// but `catch` must return `Obsrvable`
// Again, if you want an array use `Observable.from([ /* array */ ])`
return Observable.of(
new Act.GetTodoFailed({ error: error })
);
})