寻找离子 5 中事件的替代方案 [关闭]

Question

Ionic 4 组件：

import {Events} from '@ionic/angular';

 constructor(private auth: AuthService, private events: Events) {}




intercept(req: HttpRequest<any>, next: HttpHandler) {
     
 // Refresh token failed, logout user
    this.events.publish('user:logout', 'La sesión ha expirado');
    
    }

在 Ionic 5 中删除了事件... 我需要如何更改 w.t.t ionic5 ..请告诉我

EDIT ::



 import { Injectable } from '@angular/core';
    import { Subject } from 'rxjs';
    
    @Injectable({providedIn: 'root'})
    
    export class EventService{
      private formRefreshAnnouncedSource = new Subject();
      formRefreshSource$ = this.formRefreshAnnouncedSource.asObservable();
    
      publishFormRefresh(){
        this.formRefreshAnnouncedSource.next()
      }
    
    }

这个事件服务如何添加参数？

Answer 1

首先给 Su​​bject 一个类型，然后在调用 next() 时传递一个参数，如下所示：

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs';

@Injectable({providedIn: 'root'})

export class EventService{
  private formRefreshAnnouncedSource = new Subject<string>();
  formRefreshSource$ = this.formRefreshAnnouncedSource.asObservable();

  publishFormRefresh(eventName: string){
    this.formRefreshAnnouncedSource.next(eventName)
  }

}

Answer 2

您可以通过在幕后使用主题来构建自己的“事件服务”：

// app-events.enum.ts

export enum AppEvent {
  UserLogout = 'UserLogout',
  // ...
}

// app-events.service.ts

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

import { Observable, Subject } from 'rxjs';
import { filter, map } from 'rxjs/operators';

import { AppEvent } from '../enums/app-event.enum';

interface EventDetails {
  event: AppEvent;
  payload?: unknown;
}

@Injectable({ providedIn: 'root' })
export class AppEventsService {
  private eventsDispatcher = new Subject<EventDetails>();

  public dispatch(event: AppEvent, payload?: unknown): void {
    this.eventsDispatcher.next({ event, payload });
  }

  public onEvent(event: AppEvent): Observable<unknown> {
    return this.eventsDispatcher.asObservable().pipe(
      filter((eventDetails) => eventDetails.event === event),
      map((eventDetails) => eventDetails.payload),
    );
  }
}

然后你可以像这样使用它：

// dispatch
this.appEventsService.dispatch(AppEvent.UserLogout, 'La sesión ha expirado');

// listen to events
this.appEventsService
    .onEvent(AppEvent.UserLogout)
    .subscribe((message: string) => {
      console.log(message);
    });

如果您需要对有效负载中的类型提供更好的支持，我相信这可以得到改进，但它应该足以替换 Ionic 事件，因为它用于 Ionic 3。