输入'承诺<boolean | void>' 不可分配给类型 'boolean'

Question

我不明白为什么它说我不能将承诺的返回分配给布尔类型。我尝试过的任何其他方式都告诉我，我不能分配一个 void 来键入布尔值。不知道从这里做什么

我正在尝试将 checkJWT 的输出分配给承诺的解决方案。我可以这样做从逻辑上讲是有道理的，但 typescript 不喜欢它。

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';


import { NotificationService } from '../index';
import { UserInterface } from '../../../models/index';

@Injectable({
  providedIn: 'root'
})
export class AuthService {

  constructor( 
    private notificationService: NotificationService,
    private httpClient: HttpClient
   ) { }

  checkJWT(role):boolean {
    let canVisit: boolean = this.httpClient.get(window.location.protocol + '//' + window.location.hostname + ':3000/authenticate')
    .toPromise()
    .then(
      (user: UserInterface) => { 
        return role === user.role;
    }
    ) .catch((err) => { this.notificationService })
    return canVisit;
  }

Answer 1

试试这个

checkJWT(role):Promise<boolean>{
    let canVisit: Promise<boolean>= <Promise<boolean>>this.httpClient.get(window.location.protocol + '//' + window.location.hostname + ':3000/authenticate')
    .toPromise()
    .then(
      (user: UserInterface) => { 
        return role === user.role;
    }
    ) .catch((err) => { this.notificationService })
    return canVisit;
  }

因为this.httpClient.get().toPromise() 正在返回一个Promise 对象