未捕获（承诺）：错误：无效的CanActivate守卫

Question

我是角度7的newbee，现在正尝试实现CanActive，但出现错误：

任何人都可以引导我克服这一问题。我的代码示例如下：

auth.guard.ts：

import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { Observable } from 'rxjs';
import { AuthService } from './auth-service.service';
import {Router} from '@angular/router';

@Injectable({
 providedIn: 'root'
})
export class AuthGuard implements CanActivate {
constructor(private auth: AuthService,
private myRoute: Router){
}

canActivate(
next: ActivatedRouteSnapshot,
state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
if(this.auth.isLoggednIn()){
  return true;
}else{
  this.myRoute.navigate(["login"]);
  return false;
}
  }
}

Answer 1

请尝试以下操作：

   return this.auth.isLoggednIn() ? true : this.myRoute.navigate(["login"]);

执行以下操作时，我收到相同的错误消息：

   canDeactivate(component: CreateEmployeeComponent): boolean {
        if(component.createEmployeeForm.dirty) {
           return confirm('Are you sure you want to discard your changes?');
        }
        return true;
   }

所以我通过以下方式解决了这个问题：

    canDeactivate(component: CreateEmployeeComponent): boolean {
         return component.createEmployeeForm.dirty 
                ? confirm('Are you sure you want to discard your changes?') 
                : true;    
    }

我不确定它是否适合您，但您至少可以尝试一下。

Answer 2

在if条件下使用promise始终是个坏主意，因为它无法解决。您可以返回承诺本身，使用resolve将结果布尔值进一步传递给行：

canActivate(
next: ActivatedRouteSnapshot,
state: RouterStateSnapshot): Promise<boolean> | boolean {
   return new Promise(resolve =>
     this.auth.isLoggednIn()
       .then(status: boolean => {
         if(status === false) {
           this.myRoute.navigate(["login"]);
         }
         resolve(status);
       })
       .catch(() => {
         this.myRoute.navigate(["login"]);
         resolve(false);
         // ... or any other way you want to handle such error case
       })
  }
}

Answer 3

检查提供给路由的类（在本例中为 struct BookReader: App { @StateObject var library = Library() var body: some Scene { WindowGroup { LibraryView() .environmentObject(library) } } } struct LibraryView: View { @EnvironmentObject var library: Library // ... } ）MyGuardClass 实现了 {path: 'aPath', component: myComponent, canActivate: [MyGuardClass]} as documented here