Question

我具有使用update api更新对象的一部分的以下效果，然后我通过findById api获取了整个对象，因此我使用forkJoin来组合这两个对象api，但是我希望findById api可以在update api上执行1秒后执行，所以我使用了delay(1000)，但是它不起作用

@Effect()
updateGeographicScope$ = this.actions$.pipe(
    ofType<conventionsActions.PatchGeographicScope>(conventionsActions.ConventionActionTypes.PATCH_GEOGRAPHIC_SCOPE),
    map(action => action.payload),
    exhaustMap(geographicScope => forkJoin(this.apiConvention.update(geographicScope),
        this.apiConvention.findById (geographicScope.externalId).pipe(delay(1000))).pipe(
            map(([first, convention]) => new conventionsActions.PatchSuccess({
                id: convention.externalId,
                changes: convention
            })),
            catchError(err => {
                console.error(err.message);
                return of(new conventionsActions.Failure({ concern: 'PATCH', error: err }));
            })
        ))
);

Answer 1

为此，您需要使用concat和timer。使用concat，它是在开始下一个流之前要完成的第一个流。因此，它将进行更新，然后等待1秒钟，然后进行findById。

@Effect()
updateGeographicScope$ = this.actions$.pipe(
    ofType<conventionsActions.PatchGeographicScope>(conventionsActions.ConventionActionTypes.PATCH_GEOGRAPHIC_SCOPE),
    map(action => action.payload),
    mergeMap(geographicScope => concat(
      this.apiConvention.update(geographicScope).pipe(switchMapTo(EMPTY)), // makes a request
      timer(1000).pipe(switchMapTo(EMPTY)), // waits 1 sec
      this.apiConvention.findById(geographicScope.externalId), // makes a request
    )),
    map(convention => new conventionsActions.PatchSuccess({
      id: convention.externalId,
      changes: convention
    })),
    catchError(err => {
      console.error(err.message);
      return of(new conventionsActions.Failure({ concern: 'PATCH', error: err }));
    }),
    repeat(), // make active after a failure
  )),
);

ngrx效果-结合两个API

1 个答案: