"Slow requests are commonly causing performance problems in Angular apps. Here is an interceptor that can log your HTTP requests, so you can measure the roundtrip time for your requests" from https://twitter.com/chrislydemann at https://twitter.com/chrislydemann/status/1182282767935123457?s=20

interceptor.ts

import {
  HttpEvent,
  HttpHandler,
  Httpinterceptor,
  HttpRequest
} from "@angular/common/http";
import { Injectable } from "@angular/core";
import * as moment from "moment";
import { Observable } from "rxjs";
import { tap } from "rxjs/operators";

import { LogService } from "./log.service";

@Injectable({ providedln: "root" })
export class LogHttpInterceptor implements Httpinterceptor {
  constructor(private logService: LogService) {}

  public intercept(
    oldReq: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {
    const requestBeginTime = moment();
    return next.handle(oldReq).pipe(
      tap(_ => {
        this.logTime(requestBeginTime, oldReq.url, oldReq.method);
      })
    );
  }

  private logTime(startMoment: moment.Moment, url: string, method: string) {
    const requestDuration = moment().diff(startMoment, "milliseconds.");

    this.logService.logHttpInfo(`HTTP ${method}`, requestDuration, url);
  }
}