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The Angular Masterclass

Error Handling Operators

Explore how to handle errors in Angular applications using RxJS operators such as catchError, retry, and retryWhen. Understand how these operators help manage faulty Observables, retry operations based on conditions or attempts, and maintain application responsiveness.

We'll cover the following...

Error Handling Operators in RxJS

All applications need error handling, and thankfully RxJS supplies a way of handling errors when working with Observables.

catchError() operator

The catchError() operator allows us to either throw an error if we encounter an error when using a source Observable or switch to a new Observable if there is an error.

Example

See the code given below.

C++
const { of } = require("rxjs");
const { map, catchError } = require("rxjs/operators");
of(1, 2, 3, 4, 5)
  .pipe(
    map((n) => {
      // when n is 4 the error is thrown
      if (n == 4) {
        throw "four!";
      }
      return n;
    }),
    catchError((err) => of("I", "II", "III", "IV", "V"))
  )
  .subscribe((x) => console.log(x));

Looking at this example, we can see how the catchError() operator creates a new ...