RxJs How raise exception in ReplaySubject?

Question

I have an angular 2 service

import * as localforage from "localforage";
import { ReplaySubject } from 'rxjs/ReplaySubject';

@Injectable()
export class CommentService {
    private localForage = require("localforage");

    addComment (myvalue: string): Observable<Comment[]> {
        var reply:ReplaySubject<any> = new ReplaySubject(1);
        localforage.setItem(that.key, that.elencoCommenti).then(function (value) {
            //throw new Error("Value cannot be 3");
            reply.throw(Error('Error2'));           
            //              reply.next( value );
            //              reply.complete();
        });
        return reply;
    }

}

This service cointains a method for raise an exception. When i try to subscribe

submitComment(){
    // Variable to hold a reference of addComment
    let commentOperation:Observable<string>;

    commentOperation = this.commentService.addComment(this.model)

    // Subscribe to observable
    commentOperation.subscribe(
                            comments => {
                                console.log('ok:');
                                console.log(comments);
                            }, 
                            err => {
                                // Log errors if any
                                console.log('error:');
                                console.log(err);
                            });
}

i don't receive the error. How raise exception in ReplaySubject?

Answer 1

reply.error("some error"); should do it.

---

However I would not suggest you to throw an error in a ReplaySubject - as any error will finalize the Subject and make it unusable for any future use and will automatically unsubscribe any subscribers - unless that is what you want to achieve here.