在canDeactivate中使用警报

Question

我想在canDeactivate中用Alertify确认替换经典的确认。我试图实现以下代码，但当单击OK时，它没有返回True。有人对此有什么建议吗？

import { Injectable } from '@angular/core';
import { CanDeactivate } from '@angular/router';
import { SignupComponent } from 'src/app/signup/signup.component';
import { AlertifyService } from 'src/app/_helpers/alertify.service';

@Injectable()
export class SignUpPUS implements CanDeactivate <SignupComponent> {

constructor(private alertifyService: AlertifyService) {}

canDeactivate(component: SignupComponent) {
    if (component.signUpForm.dirty) {

         this.alertifyService.confirm('Leave Page', 'Are you sure you want to continue? Any unsaved changes will be lost', () => {
            return true;
        });

    }
    return false;
}

}

Answer 1

在confirm执行异步操作时，您需要使用Observable、Promise或async/await等异步解决方案。

您可以按如下方式使用Observable：

canDeactivate(component: SignupComponent) {
    return new Observable((observer) => {

        if (component.signUpForm.dirty) {

             this.alertifyService.confirm('Leave Page', 'Are you sure you want to continue? Any unsaved changes will be lost', 
               () => {
                 observer.next(true);
               },
               () => {
                 observer.next(false);
               }
             );
        }else{
           observer.next(false);
        }

        observer.complete();
    });

}

编辑注意:请注意，我为confirm添加了第二个回调，以确保在用户取消确认时返回false。

Answer 2

我不得不做一些细微的改变来让它工作起来...但是接近@Harun Yimaz的答案..

AlertifyService.ts

import * as alertify from 'alertifyjs';

  confirmCancel(
    message: string,
    okCallback: () => any,
    cancelCallback: () => any
  ) {
    alertify.confirm(message, okCallback, cancelCallback);
  }

在guard.ts中

constructor(private alertify: AlertifyService) {}

canDeactivate(component: MemberEditComponent) {
    return new Observable<boolean>(observer => {
      if (component.editForm.dirty) {
        this.alertify.confirmCancel(
          'Are you sure you want to continue? Any unsaved changes will be lost',
          () => {
            observer.next(true);
            observer.complete();
          },
          () => {
            observer.next(false);
            observer.complete();
          }
        );
      } else {
        observer.next(true);
        observer.complete();
      }
    });

必须在next之后调用observer.complete()，以便observable正确完成。