With RxJS 5.5+, the catch operator is now deprecated. You should now use the catchError operator in conjunction with pipe.
RxJS v5.5.2 is the default dependency version for Angular 5.
For each RxJS Operator you import, including catchError you should now import from 'rxjs/operators' and use the pipe operator.
import { Observable } from 'rxjs';
import { catchError } from 'rxjs/operators';
...
export class ExampleClass {
constructor(private http: HttpClient) {
this.http.request(method, url, options).pipe(
catchError((err: HttpErrorResponse) => {
...
}
)
}
...
}
Notice here that catch is replaced with catchError and the pipe operator is used to compose the operators in similar manner to what you're used to with dot-chaining.
See the rxjs documentation on pipable (previously known as lettable) operators for more info.