UserGalileo

// Injection Token
const APP_CONFIG = new InjectionToken<AppConfig>('Your description!');
const appConfig: AppConfig = { ... }

// The provider's configuration.
// At this point, whoever injects APP_CONFIG gets this object.
// But APP_CONFIG is not a class! How do we grab it?...
@NgModule({
  ...,
  providers: [{ provide: APP_CONFIG, useValue: appConfig }]

UserGalileo

import { Injectable } from '@angular/core';
import {
  HttpRequest, HttpResponse,
  HttpInterceptor, HttpHandler
} from '@angular/common/http';

import { of } from 'rxjs';
import { startWith, tap } from 'rxjs/operators';

@Injectable()

UserGalileo

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>> {

UserGalileo

import { Component, ViewChild } from '@angular/core';
import {
  AbstractControl,
  FormArray,
  FormBuilder,
  FormControl,
  FormGroup,
  FormGroupDirective, NgForm, ValidationErrors, ValidatorFn,
  Validators
} from '@angular/forms';