[英]How to make sure that the Observable.map only executed on succes?
我只是想確保map
函數中的代碼應該只在成功時調用,而不是在失敗時調用。
delete(department: Department): Observable<Department[]> {
return this.post('/delete', body).map(response => {
let index: number = this.departments.indexOf(department);
if (index > -1) {
this.departments.splice(index, 1);
}
return this.departments;
});
}
我不知道map
的代碼是否只在成功時執行。 而且,我必須返回一個Observable
所以,我不能在這里應用subscribe
功能。
Observable#map
操作符將僅在成功響應時執行(例如狀態 200)。 Observable#catch
運算符旨在捕獲故障。
此外, Observable#catch
操作符也將捕獲映射成功響應時拋出的 javascript 錯誤。 例子:
fetchDashboardData(): Observable<Dashboard> {
return this._http.get(reqUrl, reqOptions)
.map((response: Response) => new Dashboard(response.json().items[0].dashboard))
.catch((error: any) => {
if (error instanceof Error) {
// js error, e.g. response.json().items was an empty array
console.log(error); // => “Cannot read property 'dashboard' of undefined...
return Observable.throw('Incomplete response data!');
} else {
return Observable.throw('Server error!');
}
});
}
訂閱塊:
this.dashboardService.fetchDashboardData().subscribe(
(dashboard: Dashboard) => {
this.dashboard = dashboard;
console.log('Success fetching dashboard data!', dashboard);
},
(errMssg: string) => {
console.error(errMssg); // => 'Incomplete response data!'
// or 'Server error!'
},
() => {
// finally block!
}
);
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.