Angular 9/rxjs:如何处理switchMap内部抛出的错误？
Angular 9/rxjs:如何处理switchMap内部抛出的错误？
提问于 2020-06-25 04:17:46
我使用的是Angular (9) powered Bootstrap (6.1.0) TypeAhead，它的搜索函数定义如下：
search = (text$: Observable<string>) => {
return text$.pipe(
debounceTime(200),
distinctUntilChanged(),
// switchMap allows returning an observable rather than maps array
switchMap((searchText) => {
if (!searchText || searchText.trim().length == 0) {
// when the user erases the searchText
this.dealerRepUserID = 0;
this.dealerRepChanging.emit(this.dealerRepUserID);
return EMPTY;
}
else if (this.dealerID == this.hostOrganizationID) {
// get a list of host reps
return this.myService.getHostRepsAutoComplete(searchText, this.includeInactive);
} else {
// get a list of dealer reps
return this.myService.getDealerReps(this.dealerID, searchText);
}
})
);
}该函数必须返回一个可观察对象。如何捕获在switchMap中抛出的错误？
回答 2
Stack Overflow用户
回答已采纳
发布于 2020-06-25 04:24:32
你试过catchError吗？
import { catchError } from 'rxjs/operators';return text$.pipe(
debounceTime(200),
distinctUntilChanged(),
// switchMap allows returning an observable rather than maps array
switchMap((searchText) => {
if (!searchText || searchText.trim().length == 0) {
// when the user erases the searchText
this.dealerRepUserID = 0;
this.dealerRepChanging.emit(this.dealerRepUserID);
return EMPTY;
}
else if (this.dealerID == this.hostOrganizationID) {
// get a list of host reps
return this.myService.getHostRepsAutoComplete(searchText, this.includeInactive).pipe(catchError(error => of());
} else {
// get a list of dealer reps
return this.myService.getDealerReps(this.dealerID, searchText).pipe(catchError(error => of());
}
})
);这是我的应用效果
public loadDataPerformance$: Observable<Action> = createEffect(() => {
return this.actions$.pipe(
ofType(RiskProfileActions.loadDataPerformance),
withLatestFrom(
this.store$.select(fromRoot.getAnalyticsFilterSelectedOptions),
this.store$.pipe(select(fromFactoryPerformance.getFactoryId))
),
switchMap(([{ recordDate }, filters, factoryId]) =>
this.riskProfileApiService.getDataPerformanceData(filters, factoryId, recordDate).pipe(
map((riskDataPerformanceData: PerformanceDataModel) =>
RiskProfileActions.loadRiskScoreBreakdownPerformanceSuccess(riskDataPerformanceData)
),
catchError(error => of(RiskProfileActions.loadRiskScoreBreakdownPerformanceFail(error)))
)
)
);
});Stack Overflow用户
发布于 2020-06-25 10:14:02
switchMap本身不会抛出任何错误，可能会产生意想不到的事情是返回的可观察对象this.myService.getHostRepsAutoComplete和this.myService.getDealerReps。捕获错误的一个棘手时刻是，每当有error时，抛出错误的可观察对象就会被杀死。
例如
observable$.pipe(
switchMap(() => observable2$),
catchError(() => doSomethingFunction())
).subscribe()一旦出现错误，observable$将被完成，这将完成您的搜索流，错误发生后，您将不会获得更多数据。
正如Phat Tran Ky在他的示例中所展示的那样，错误的处理应该发生在switchMap操作符的新流中
observable$.pipe(
switchMap(() => observable2$.pipe(catchError(() => doSomethingFunction())),
)
).subscribe()这样，每当内部抛出错误时，它将终止内部可观察对象(observable2$)，但不会终止外部可观察对象observable$上的外部订阅
为了在一个点处理错误，您可以执行的进一步增强可能是将内部可观察对象合并到一个点中，例如，如下所示
observable$.pipe(
switchMap(() => {
return merge(
observable1$.pipe(filter(() => ${your if else condition for case 1})),
observable2$.pipe(filter(() => ${your if else condition for case 2})),
observable3$.pipe(filter(() => ${your if else condition for case 3})),
).pipe(catchError((error) => yourErrorHandlerFunction(error)))
})),
)
).subscribe()页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/62567799
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