Angular5 HttpInterceptor depending on the result of an Observable

Question

I am trying to implement using Angular5 an HttpInterceptor to inject an Authorization header in all HTTP requests.

I rely on a third party library (ADAL

Answer 1

possible issue is here

 constructor(private auth: AuthService) { }

the provider is not available inside the interceptor

solution

use Injector to inject your service

// 1. import the injector
import { Injectable, Injector } from '@angular/core';
// 2. create a constant of your service
private auth: AuthService;
// 3. add injector into contsructor; remove authService from constructor
constructor(private injector: Injector) { }
// 4. now create instance of your service inside intercept()
intercept() {
const auth = this.injector.get(AuthService);
// 5. now call method on this auth object