JWT Interceptor

jwt.interceptor.ts

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

import { AuthenticationService } from '@/_services';

@Injectable()
export class JwtInterceptor implements HttpInterceptor {
    constructor(private authenticationService: AuthenticationService) {}

    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        // add authorization header with jwt token if available
        let currentUser = this.authenticationService.currentUserValue;
        if (currentUser && currentUser.token) {
            request = request.clone({
                setHeaders: { 
                    Authorization: `Bearer ${currentUser.token}`
                }
            });
        }

        return next.handle(request);
    }
}

z-app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { ReactiveFormsModule } from '@angular/forms';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';

// used to create fake backend
import { fakeBackendProvider } from './_helpers';

import { appRoutingModule } from './app.routing';
import { JwtInterceptor, ErrorInterceptor } from './_helpers';
import { AppComponent } from './app.component';
import { HomeComponent } from './home';
import { LoginComponent } from './login';
import { RegisterComponent } from './register';
import { AlertComponent } from './_components';

@NgModule({
    imports: [
        BrowserModule,
        ReactiveFormsModule,
        HttpClientModule,
        appRoutingModule
    ],
    declarations: [
        AppComponent,
        HomeComponent,
        LoginComponent,
        RegisterComponent,
        AlertComponent
    ],
    providers: [
        { provide: HTTP_INTERCEPTORS, useClass: JwtInterceptor, multi: true },
        { provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true },

        // provider used to create fake backend
        fakeBackendProvider
    ],
    bootstrap: [AppComponent]
})
export class AppModule { };