Retry Interceptor

retry.interceptor.ts

import {HttpContextToken, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest} from '@angular/common/http';
import {Observable} from 'rxjs';
import {retry, tap} from 'rxjs/operators';

export const RETRY_COUNT = new HttpContextToken(() => 3);
export const ERROR_COUNT = new HttpContextToken(() => 0);

export class RetryInterceptor implements HttpInterceptor {
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

    const retryCount = req.context.get(RETRY_COUNT);

    return next.handle(req).pipe(
        tap({
          error: () => {
            req.context.set(ERROR_COUNT, req.context.get(ERROR_COUNT) + 1);
          },
        }),
        retry(retryCount)
    );
  }
}

/**
 * Usage:
 * 
    this.httpClient.get('...', {
      context: new HttpContext().set(RETRY_COUNT, 5),
    }).subscribe(() => {});
 */