從 catchError 中的 return observable 獲取值

Question

budgetTestService.getBudgetDates返回一個 observable，如何在BudgetDate[]從中獲取BudgetDate[]值？

this.budgetService.getBudgetDays(this.startDate, this.finishDate)
  .pipe(
    catchError(error => {
      self.timelineBudgetDates = self.budgetTestService.getBudgetDates(self.startDate, self.finishDate);
        return of('some return value');
      }
    )
  )
  .subscribe(res => {
    self.timelineBudgetDates = self.processDates(res);          
  });

錯誤：

Type 'Observable<BudgetDate[]>' is missing the following properties from type 'BudgetDate[]': length, pop, push, concat, and 25 more.

Answer 1

您可以使用高階函數將此引用傳遞給 catch

const errorHandler=(self)=>error => {
              self.timelineBudgetDates = 
              self.budgetTestService.getBudgetDates(self.startDate, self.finishDate);
              return of('some return value');
            }
          )

this.budgetService.getBudgetDays(this.startDate, this.finishDate)
        .pipe(
          catchError(errorHandle(this))
        )
        .subscribe(res => {
          self.timelineBudgetDates = self.processDates(res);

        });

Answer 2

如果您從組件調用 budgetService，您應該能夠在無需訂閱的情況下映射響應。 catchError 僅在服務拋出錯誤時執行。 請看下面的代碼...

    this.budgetService.getBudgetDays(this.startDate, this.finishDate)
        .pipe(
          map(res => { self.timelineBudgetDates = self.processDates(res); }), 
          catchError(error => {
              // handle error
            })
         );