在 Jwthelperservice 中出现错误

Question

我对 Angular 很陌生，我获取了代码：

网址 = https://github.com/DavideViolante/Angular-Full-Stack

import { Injectable } from '@angular/core';
import { Router } from '@angular/router';

import { JwtHelperService } from '@auth0/angular-jwt';

import { UserService } from './user.service';
import { HttpClient } from '@angular/common/http';
import { User } from '../shared/models/user.model';

import 'rxjs/add/operator/map';

@Injectable()
export class AuthService {
  loggedIn = false;
  isAdmin = false;

  currentUser: User = new User();

  constructor(private userService: UserService,
              private http: HttpClient,
              private router: Router,
              private jwtHelper: JwtHelperService) {
    const token = localStorage.getItem('token');
    if (token) {
      const decodedUser = this.decodeUserFromToken(token);
      this.setCurrentUser(decodedUser);
    }
  }

  login(emailAndPassword) {
    return this.userService.login(emailAndPassword).map(
      res => {
        localStorage.setItem('token', res.token);
        const decodedUser = this.decodeUserFromToken(res.token);
        this.setCurrentUser(decodedUser);
        return this.loggedIn;
      }
    );
  }

  decodeUserFromToken(token) {
    return this.jwtHelper.decodeToken(token).user;
  }
}

我正在使用 Visual Studio 代码，它没有抛出任何语法错误。

但在控制台中出现错误：

Error: StaticInjectorError(AppModule)[AuthService -> JwtHelperService]: 
  StaticInjectorError(Platform: core)[AuthService -> JwtHelperService]: 
    NullInjectorError: No provider for JwtHelperService!
    at _NullInjector.get (core.js:994)
    at resolveToken (core.js:1292)
    at tryResolveToken (core.js:1234)
    at StaticInjector.get (core.js:1102)
    at resolveToken (core.js:1292)
    at tryResolveToken (core.js:1234)

Answer 1

您必须将 AuthGuard 添加到 app.module 中的提供程序列表中：

  providers: [
    AuthGuard
  ],

Answer 2

这个错误只是因为你没有在 app 模块文件中添加 jwtmodule。所以在这里你需要添加它的配置所以，请在你的 app.module.ts 文件中添加以下代码：

import { JwtHelperService, JwtModule } from '@auth0/angular-jwt';
...
@NgModule({
imports: [
     ...
    JwtModule.forRoot({
    config: {
      tokenGetter: function  tokenGetter() { 
      return localStorage.getItem('token');
      } 
   }
 });
 ...
 ],
 ...
 })