// RxJS v6+
import { throwError } from 'rxjs';
//subscription시 정해진 값의 에러를 내보냅니다.
const source = throwError('This is an error!');
//결과: 'Error: This is an error!'
const subscribe = source.subscribe({
next: val => console.log(val),
complete: () => console.log('Complete!'),
error: val => console.log(`Error: ${val}`)
});