Error handling with the Angular SDK

The SDK uses the Angular HttpClient. Any response outside the 2xx range arrives as an HttpErrorResponse on the error channel of the Observable. It does not throw, and it does not stop your application.

Handle the error in the subscription

Pass an error callback to subscribe(). This is the simplest way to react to a failed request:

import {HttpErrorResponse} from '@angular/common/http';

this.api.listTransformsV1({filters: 'id eq'}).subscribe({
  next: (transforms) => console.log(transforms),
  error: (error: HttpErrorResponse) => {
    console.log(error.status);
    console.log(error.error);
    console.log(error.error?.trackingId);
  },
});

HttpErrorResponse carries these fields:

Field	Description
status	The HTTP status code, for example 400.
error	The parsed response body. An ISC error body holds detailCode, trackingId, messages, and causes.
headers	The response headers.
url	The URL of the failed request.
message	A summary string that Angular builds for logging.

A status of 0 means that the request never reached the server. A network failure or a CORS rejection both produce that value.

Recover and continue

Use the RxJS catchError operator to replace the error with a value. The stream then completes normally, and the next callback runs with your fallback value:

import {catchError, of, throwError} from 'rxjs';
import {HttpErrorResponse} from '@angular/common/http';

this.api
  .listTransformsV1({filters: 'id eq'})
  .pipe(
    catchError((error: HttpErrorResponse) => {
      if (error.status === 400) {
        console.log('The filter is invalid. Continuing with an empty list.');
        return of([]);
      }
      return throwError(() => error);
    }),
  )
  .subscribe((transforms) => console.log(transforms.length));

The example recovers from a 400 response and re-raises every other error. Return of([]) for every status code to make the request never fail.

Read the error message from ISC

The ISC APIs return a structured body on an error. Read error.error.messages to get the text:

error: (error: HttpErrorResponse) => {
  const messages = error.error?.messages ?? [];
  for (const message of messages) {
    console.log(message.text);
  }
},

trackingId identifies the failed request inside ISC. Include that value in a support case.

For retry behavior on a 401, a 429, or a 5xx response, refer to Retries.