Angular 6 - 添加另一个字符串进行服务

Question

我正在开发一个将消息发送到另一个组件的服务。

以下是该服务的代码：

private subject = new Subject<any>();

sendMessage(message: string) {
    this.subject.next({ text: message });
}

clearMessage() {
    this.subject.next();
}

getMessage(): Observable<any> {
    return this.subject.asObservable();
}

我想要做的是在消息之外添加另一个字符串，以便我可以随身携带它。像这样：

sendMessage(message: string, anotherstring: string) {
  this.subject.next({ text: message, anotherstring });  // This does not work
}

我想添加更多这样的参数：

this.service.sendMessage('Message from app Component to message Component!', 'somethingElse');

如何使用消息文本传递更多字符串/参数？

以下是完整代码：

message.service.ts

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

@Injectable()
export class MessageService {
    private subject = new Subject<any>();

    sendMessage(message: string) {
        this.subject.next({ text: message });
    }

    clearMessage() {
        this.subject.next();
    }

    getMessage(): Observable<any> {
        return this.subject.asObservable();
    }
}

app.component.ts

import { Component } from '@angular/core';
import { MessageService } from './message.service';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular 6';

  constructor(private service:MessageService){}

  sendMessage(): void {
        // send message to subscribers via observable subject
  this.service.sendMessage('Message from app Component to message Component!');   
  }

  clearMessage():void{
    this.service.clearMessage();
  }
}

app.component.html

<button (click)="sendMessage()">Click here to test message</button> <br><br>
<app-messagecomponent></app-messagecomponent>

message.component.ts

import { Component, OnDestroy } from '@angular/core';
import { Subscription } from 'rxjs';
import { MessageService } from './message.service';

@Component({
    selector: 'app-messagecomponent',
    templateUrl: 'message.component.html'
})

export class MessageComponent implements OnDestroy {
    message: any = {};
    subscription: Subscription;

    constructor(private messageService: MessageService) {
        // subscribe to app component messages
        this.subscription = this.messageService.getMessage().subscribe(message => { this.message = message; });
    }

    ngOnDestroy() {
        // unsubscribe to ensure no memory leaks
        this.subscription.unsubscribe();
    }
}