Use Http interceptor In Angular for Every Http Request

import { Injectable } from "@angular/core";
import { HttpInterceptor, HttpRequest, HttpResponse, HttpHandler, HttpEvent, HttpErrorResponse, HttpHeaders } from "@angular/common/http";
import { Observable, throwError } from 'rxjs';
import { map, catchError } from 'rxjs/operators';

@Injectable()

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

        const headersConfig = {
            'Accept': 'application/json'
        };
        const idToken = localStorage.getItem("token");

        if (idToken) {
            headersConfig['Authorization'] = idToken;
            let request = req.clone({
                setHeaders: headersConfig
            });
            return next.handle(request);
        }
        else {
            return next.handle(req)
        }
        // // authorization with jwt token
        // let currentUser = JSON.parse(localStorage.getItem('currentUser'));
        // if (currentUser && currentUser.token) {
        //     let request = req.clone({
        //         setHeaders: {
        //             Authorization: `Bearer ${currentUser.token}`
        //         }
        //     });
        // }

        // return next.handle(req);
    }
}

import { Injectable } from '@angular/core';
import { Observable } from "rxjs";
import { environment } from "../../../environments/environment";
import { HttpHeaders, HttpClient, HttpParams } from "@angular/common/http";
import { throwError } from "rxjs";
import { catchError, retry } from "rxjs/operators";

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  httpOptions = {
    headers: new HttpHeaders({
      "Content-Type": "application/json",
      "Access-Control-Allow-Origin": "*"
    })
  };
  constructor(private http: HttpClient) { }

  private formatErrors(error: any) {
    return throwError(error.error);
  }

  get(path: string, params: HttpParams = new HttpParams()): Observable<any> {
    return this.http.get(path, { params }).pipe(catchError(this.formatErrors));
  }

  put(path: string, body: Object = {}): Observable<any> {
    return this.http
      .put(path, JSON.stringify(body), this.httpOptions)
      .pipe(catchError(this.formatErrors));
  }

  post(path: string, body: Object = {}): Observable<any> {
    return this.http
      .post(path, JSON.stringify(body), this.httpOptions)
      .pipe(catchError(this.formatErrors));
  }

  delete(path): Observable<any> {
    return this.http.delete(path).pipe(catchError(this.formatErrors));
  }
}