Cache interceptor in Angular using a cache service

cache.interceptor.ts

import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { tap } from 'rxjs/operators';

import { HttpCacheService } from 'app/services/http-cache.service'; // https://gist.github.com/kudchikarsk/f2f8754eca3cf86db3fbbc833c330e55

@Injectable()
export class CacheInterceptor implements HttpInterceptor {

  constructor(private cacheService: HttpCacheService) { }

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

    // pass along non-cacheable requests and invalidate cache
    if(req.method !== 'GET') {
      console.log(`Invalidating cache: ${req.method} ${req.url}`);
      this.cacheService.invalidateCache();
      return next.handle(req);
    }

    // attempt to retrieve a cached response
    const cachedResponse: HttpResponse<any> = this.cacheService.get(req.url);


    // return cached response
    if (cachedResponse) {
      console.log(`Returning a cached response: ${cachedResponse.url}`);
      console.log(cachedResponse);
      return of(cachedResponse);
    }    


    // send request to server and add response to cache
    return next.handle(req)
      .pipe(
        tap(event => {
          if (event instanceof HttpResponse) {
            console.log(`Adding item to cache: ${req.url}`);
            this.cacheService.put(req.url, event);
          }
        })
      );

  }
}