Ionic upvote/downvote system + Firebase

Ionic Framework Ionic Angular
1

Hello,
I would like to add upvote/downvote system that display a count number between them on my ionic app using Firebase database + authentication. When a user is logged-in, that user can upvote/downvote someone elses posts.

Thank you so much

HTML:

<ion-card *ngFor="let post of posts">

    <ion-card-content>
    {{post.title}}
    </ion-card-content> 

    <ion-card-header>
    <ion-card-title>{{ post.details }}</ion-card-title> 
    </ion-card-header>
   
    <ion-button (click)="onClick()" fill="clear" color="dark">
    <ion-icon name="arrow-up-outline"></ion-icon>
    </ion-button>

     //I would like this button to show the numbers of upvote/downvote 
    <ion-button fill="clear">
    <ion-label color="dark">{{ }}</ion-label>
    </ion-button>

    <ion-button (click)="onClick()" fill="clear" color="dark">
    <ion-icon name="arrow-down-outline"></ion-icon>
    </ion-button>

  </ion-card>

</ion-content>

TS:

import { Component, OnInit } from '@angular/core';
import { AngularFirestoreModule } from '@angular/fire/compat/firestore';
import { LoadingController, ToastController } from '@ionic/angular';
import { AngularFirestore } from "@angular/fire/compat/firestore";

@Component({
  selector: 'app-home',
  templateUrl: './home.page.html',
  styleUrls: ['./home.page.scss'],
})
export class HomePage implements OnInit {
posts: any;

  constructor(
    private loadingCtrl: LoadingController,
    private toastCtrl: ToastController,
    private firestore: AngularFirestore,
    
  ) { }

  ngOnInit() {
  }

  ionViewWillEnter(){
this.getPosts();
  }

async getPosts(){
//show loader
let loader = this.loadingCtrl.create({
  message: "Please wait..."
});
(await loader).present();

try{
this.firestore.collection("discussion")
.snapshotChanges()
.subscribe(data => {
this.posts = data.map(e => {
  return{
    id: e.payload.doc.id,
    title: e.payload.doc.data()["title"],
    details: e.payload.doc.data()["details"],
  };
});
});

//dismiss loader
(await loader).dismiss();
} catch(e){
this.showToast(e);
}


}


showToast(message: string){
  this.toastCtrl.create({
    message: message,
    duration: 3000
  })
  .then(toastData => toastData.present());
}

}

TS:

export interface Discussion{
    title: string;
    details: string;
}
export interface User{
    email: string;
    password: string;
}