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RxJS - Error Handling Operator catchError
This operator takes care of catching errors on the source Observable by returning a new Observable or an error.
Syntax
catchError(selector_func: (err_func: any, caught: Observable) => O):Observable
Parameters
selector_funct − The selector func takes in 2 arguments, error function and caught which is an Observable.
Return value
It returns an observable based on the value emitted by the selector_func.
Example
import { of } from 'rxjs'; import { map, filter, catchError } from 'rxjs/operators'; let all_nums = of(1, 6, 5, 10, 9, 20, 40); let final_val = all_nums.pipe( map(el => { if (el === 10) { throw new Error("Testing catchError."); } return el; }), catchError(err => { console.error(err.message); return of("From catchError"); }) ); final_val.subscribe( x => console.log(x), err => console.error(err), () => console.log("Task Complete") );
Output
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