home.html

<ion-header>
  <ion-navbar>
    <ion-title>
      Apps Tajul Asri
    </ion-title>
  </ion-navbar>
</ion-header>

<ion-content padding>
  <ion-list>
  
    <ion-item>
      <ion-input type="number" text-center [(ngModel)]="formInput.harga" placeholder="Harga"></ion-input>
    </ion-item>
  
    <ion-item>
      <ion-input type="number" text-center [(ngModel)]="formInput.kuantiti" placeholder="Kuantiti"></ion-input>
    </ion-item>

    <ion-item>
      <ion-input type="number" text-center [(ngModel)]="formInput.diskaun" placeholder="Diskaun"></ion-input>
    </ion-item>
  
  </ion-list>
  <button ion-button (click)="bilaButtonKiraDiTekan()" full color="danger">Kira</button>
  <p>
    If you get lost, the <a href="http://ionicframework.com/docs/v2">docs</a> will be your guide.
  </p>
</ion-content>

home.ts

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';
import { AlertController } from "ionic-angular";

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})

export class HomePage {

  //form kita ada 3 attributes
  //harga
  //kuantiti
  //diskaun

  //model
  formInput = {
    harga: 0,
    kuantiti: 1,
    diskaun: 0
  }

  constructor(public alertCtrl: AlertController,public navCtrl: NavController) {

  }

  bilaButtonKiraDiTekan() {
    //kita sediakan pemboleh ubah yang berkemungkinan
    var hargaProduct = this.formInput.harga;
    var kuantiti = this.formInput.kuantiti;
    var diskaun = this.formInput.diskaun;
    //kita cuba kira discount
    var less = diskaun / 100;
    //jumlah harga barang tanpa potongan
    var hargaAsalBarang = hargaProduct*kuantiti;
    //jumlah diskaun potongan bentuk 0/100 kena darab
    //dengan harga barang asal
    //jumlah pembelian diskaun setiap barang didarab
    // dengan bilangan kuantiti
    var diskaunKeseluruhan = (less * hargaProduct) * kuantiti;
    var hargaSelepasPotongan = hargaAsalBarang - diskaunKeseluruhan;
    console.log(hargaSelepasPotongan);

    var tukarKepadaFormatHarga = hargaSelepasPotongan.toFixed(2);


    const alert = this.alertCtrl.create({
      title: 'Keputusan pengiraan',
      subTitle: 'RM ' + tukarKepadaFormatHarga,
      buttons: ['OK']
    });
    alert.present();
  }

}