Training

db.json

@@ -4,13 +4,13 @@
       "id": 1,
       "name": "Sprite",
       "cost": 0.5,
-      "remaining": 10
+      "remaining": 4
     },
     {
       "id": 2,
       "name": "Coke",
       "cost": 0.5,
-      "remaining": 10
+      "remaining": 9
     },
     {
       "id": 3,

src/app/app.component.html

@@ -2,3 +2,4 @@ <h1>
   {{title}}
 </h1>
 <app-insert-coin></app-insert-coin>
+<app-dispense-item></app-dispense-item>

src/app/app.module.ts

@@ -8,11 +8,13 @@ import { InsertCoinComponent } from './insert-coin/insert-coin.component';
 
 import { ItemService } from './item/item.service';
 import { BalanceService } from './balance/balance.service';
+import { DispenseItemComponent } from './dispense-item/dispense-item.component';
 
 @NgModule({
   declarations: [
     AppComponent,
-    InsertCoinComponent
+    InsertCoinComponent,
+    DispenseItemComponent
   ],
   imports: [
     BrowserModule,

src/app/dispense-item/dispense-item.component.html

@@ -0,0 +1 @@
+<button class="button -full-width" (click)="dispenseItem()">dispense</button>

src/app/dispense-item/dispense-item.component.spec.ts

@@ -0,0 +1,28 @@
+/* tslint:disable:no-unused-variable */
+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+import { By } from '@angular/platform-browser';
+import { DebugElement } from '@angular/core';
+
+import { DispenseItemComponent } from './dispense-item.component';
+
+describe('DispenseItemComponent', () => {
+  let component: DispenseItemComponent;
+  let fixture: ComponentFixture<DispenseItemComponent>;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [ DispenseItemComponent ]
+    })
+    .compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(DispenseItemComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+  });
+
+  it('should create', () => {
+    expect(component).toBeTruthy();
+  });
+});

src/app/dispense-item/dispense-item.component.ts

@@ -0,0 +1,31 @@
+import { Component, OnInit } from '@angular/core';
+import { ItemService } from '../item/item.service';
+import { BalanceService } from '../balance/balance.service';
+
+@Component({
+  selector: 'app-dispense-item',
+  templateUrl: './dispense-item.component.html',
+  styleUrls: ['./dispense-item.component.scss'],
+  providers: []
+})
+export class DispenseItemComponent implements OnInit {
+
+  constructor(private itemService: ItemService, private balanceService: BalanceService) { }
+
+  ngOnInit() {
+    dispenseItem() {
+      const currentBalance = this.balanceService.getBalance();
+      if (!this.itemService.hasSufficientBalance(currentBalance)) {
+        alert("insufficient balance");
+      } else if (!this.itemService.hasRemaining()) {
+        alert("none remaining");
+      } else {
+        // itemSerice.dispenseItem
+        this.itemService.dispenseItem((item) => {
+          alert('Enjoy your ' + item.name);
+          this.balanceService.deductBalance(item.cost);
+        })
+      }
+    }
+  }
+}