What are some effective error handling strategies in NgRx?

What are some effective error handling strategies in NgRx?

In NgRx, you can handle errors using effects, reducers, and services. One common strategy is to catch errors in effects and dispatch an error action.

Can you give me an example of how to implement error handling in an effect?

Sure! You can use the catchError operator in your effect. For example:

loadData$ = createEffect(() => this.actions$.pipe(
  ofType(loadData),
  switchMap(() => this.dataService.getData().pipe(
    map(data => loadDataSuccess({ data })),
    catchError(error => of(loadDataFailure({ error })))
  ))
));

What should I do with the error action in the reducer?

In the reducer, you can handle the error action by updating the state to reflect the error. For example:

on(loadDataFailure, (state, { error }) => ({
  ...state,
  error: error,
  loading: false
}));

How can I display error messages in the UI?

You can select the error state from the store and display it in your component. For example:

this.store.select(selectError).subscribe(error => {
  if (error) {
    this.errorMessage = error;
  }
});