base.url Angular 5

APIhttp.interactor.ts

import { Injectable } from '@angular/core';
import {HttpEvent, HttpInterceptor, HttpHandler, HttpRequest} from '@angular/common/http';
import {Observable} from 'rxjs/Observable';
import { environment } from "../../../../environments/environment";


@Injectable()
export class APIHttpInterceptor implements HttpInterceptor {

  private baseUrl: string = environment.API_BASE_URL;

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

    const apiReq = req.clone({ url: `${this.baseUrl}/${req.url}` });
    return next.handle(apiReq);
  }
}

app.module.ts

import {BrowserModule} from '@angular/platform-browser';
import {NgModule} from '@angular/core';

import {AppRoutingModule} from './app-routing.module';

import {AppComponent} from './app.component';
import {HttpClientModule, HTTP_INTERCEPTORS} from '@angular/common/http';
import {APIHttpInterceptor} from "./system/shared/interactors/APIhttp.interactor";

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule
  ],
  providers: [{
    provide: HTTP_INTERCEPTORS,
    useClass: APIHttpInterceptor,
    multi: true
  }],
  bootstrap: [AppComponent]
})
export class AppModule {
}