src/app/util/rxjs/rxjs.util.ts

/********************************************************************************
 * Copyright (c) 2020 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0
 *
 * SPDX-License-Identifier: EPL-2.0
 ********************************************************************************/

import {EMPTY, OperatorFunction, pipe, throwError, timer} from "rxjs";
import {catchError, concatMap, map, retryWhen} from "rxjs/operators";

/**
 * If an error occurs, the observable is repeated after a given amount of time.
 * @param timeInMs Time in miliseconds after which the observable is repeated.
 * @param count Number of times the observable shall be repeated; if not specified, the observable is repeated until completion.
 */
export function retryAfter<T>(timeInMs: number, count?: number) {
    let counter = 0;
    return pipe(
        retryWhen<T>((errors) => {
            return errors.pipe(
                concatMap((error) => {
                    if (typeof count === "number" && counter > count) {
                        return throwError(error);
                    }
                    counter++;
                    return timer(timeInMs).pipe(map(() => error));
                })
            );
        })
    );
}

/**
 * If an error occurs, error is just ignored and the observable is finished without emitting any values.
 */
export function ignoreError<T>(): OperatorFunction<T, T> {
    return catchError((err) => {
        console.error(err);
        return EMPTY;
    });
}