Bug-1 (Octane)

components.candy-item.js

import Component from '@ember/component';
import { computed, action } from '@ember-decorators/object';
import { and } from '@ember-decorators/object/computed';
import { classNames, tagName } from '@ember-decorators/component';

@tagName('li')
@classNames('candy-item')
export default class CandyItem extends Component {
  @and('discount.{couponNotUsed,percent}', 'isOnSale') isDiscountAllowed

  @computed('discount.percent')
  get discountedPrice() {
    const price = this.price;
    const discountPercent = this.get('discount.percent');
    return price * (1 - discountPercent);
  }

  // DEMO[1]: used to be BAD without classes - proto error. Not anymore with class syntax
  discount = {
    couponNotUsed: true,
    percent: 0.1
  };

  @action
  applyCoupon() {
    const discountedPrice = this.discountedPrice;
    this.set('isCouponApplied', true);
    this.set('discount.couponNotUsed', false);
    this.set('price', discountedPrice);
  }
}

controllers.application.js

import Controller from '@ember/controller';
import { get, set, observer } from '@ember/object';
import { computed, action } from '@ember-decorators/object';

export default class ApplicationController extends Controller {
  // DEMO[3]: BAD - Observer vs computed properties
  /* amountSavedObs: observer('model.cartItems.@each.{originalPrice,price,qty}', function() {
    console.log('totalSavings - Observer');
    // TODO: can we listen to `isOnSale` as well, to amplify the problem with observer ?
    let _totalAmountSaved = 0;
    const cartItems = this.model.cartItems;
    cartItems.forEach(item => {
      _totalAmountSaved += (item.originalPrice - item.price) * item.qty;
    });
    _totalAmountSaved = _totalAmountSaved.toFixed(2);
    this.set('totalSavings', _totalAmountSaved);
  }), */

  // DEMO[3]: GOOD - Observer vs computed properties
  @computed('model.cartItems.@each.{originalPrice,price,qty}')
  get totalSavings() {
    console.log('totalSavings - Computed Property');
    let _totalAmountSaved = 0;
    const cartItems = this.model.cartItems;
    cartItems.forEach(item => {
      _totalAmountSaved += (item.originalPrice - item.price) * item.qty;
    });
    _totalAmountSaved = _totalAmountSaved.toFixed(2);
    return _totalAmountSaved;
  }

  @computed('model.cartItems.@each.{qty,price}')
  get totalAmount() {
    const cartItems = this.model.cartItems;
    let _totalAmount = 0;
    cartItems.forEach(item => (_totalAmount += item.qty * item.price));
    return _totalAmount;
  }

  // DEMO[2.2]: BAD - listening to `model.cartItems.[]` vs `model.cartItems`
  /* uniqueChocolatesCount: computed('model.cartItems', function() {
    return this.model.cartItems.length;
  }), */

  // DEMO[2.2]: GOOD - listening to `model.cartItems.[]` vs `model.cartItems`
  @computed('model.cartItems.[]')
  get uniqueChocolatesCount() {
    return this.model.cartItems.length;
  }

  @action
  addToCart(candyId) {
    const cartItems = this.model.cartItems;
    const targetCandy = cartItems.findBy('id', candyId);

    if (targetCandy) {
      const qty = targetCandy.qty;
      set(targetCandy, 'qty', qty + 1);
    } else {
      const catalogue = this.model.candies;
      const newCandyLineItem = catalogue.findBy('id', candyId);
      set(newCandyLineItem, 'qty', 1);

      // DEMO[2.1]: BAD - KVO
      /* cartItems.push(newCandyLineItem);
        console.log(cartItems); */

      // DEMO[2.1]: GOOD - KVO
      cartItems.pushObject(newCandyLineItem);
    }
	}
   
   @action
   resetCart() {
     this.set('model.cartItems', []);
   }
}

routes.application.js

import Route from '@ember/routing/route';

export default class ApplicationRoute extends Route {
  model() {
    return {
      candies: [
        {
          id: '1',
          name: 'Ferrero',
          url: 'http://i64.tinypic.com/mjn2h5.jpg',
          price: 10,
          originalPrice: 10,
          isOnSale: true
        },
        {
          id: '2',
          name: 'Lindt',
          url: 'http://i65.tinypic.com/14btfrr.png',
          price: 8,
          originalPrice: 8,
          isOnSale: false
        },
        {
          id: '3',
          name: 'Hersheys',
          url: 'http://i68.tinypic.com/2vtbi3m.jpg',
          price: 8,
          originalPrice: 8,
          isOnSale: true
        },
        {
          id: '4',
          name: 'Kisses',
          url: 'http://i64.tinypic.com/2vnm7bm.png',
          price: 10,
          originalPrice: 10,
          isOnSale: false
        }
      ],

      cartItems: []
    };
  }
}

styles.app.css

body {
  font-family: Arial, Helvetica, sans-serif;
  background-color: #f5f5f5; }

.app-name {
  font-family: -apple-system, system-ui, BlinkMacSystemFont, Segoe UI, Roboto, Helvetica Neue, Fira Sans, Ubuntu, Oxygen, Oxygen Sans, Cantarell, Droid Sans, Apple Color Emoji, Segoe UI Emoji, Segoe UI Emoji, Segoe UI Symbol, Lucida Grande, Helvetica, Arial, sans-serif;
  font-size: 20px;
  line-height: 28px;
  font-weight: 400;
  color: #000000e6; }

.ember-application {
  padding: 20px; }

.catalogue {
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 20px; }

.rounded-border {
  border-radius: 100%; }

.candy-list {
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 20px; }
  .candy-list .candy-item {
    background-color: #fff;
    border: 1px solid #efefef;
    padding: 10px;
    box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.15), 0 4px 6px rgba(0, 0, 0, 0.2);
    transition: box-shadow 83ms; }
    .candy-list .candy-item:hover {
      box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.15), 0 8px 12px rgba(0, 0, 0, 0.2); }
  .candy-list .btn-coupon {
    padding: 4px 12px;
    cursor: pointer;
    background-color: #ef7e37;
    color: #fff;
    text-transform: capitalize;
    border-radius: 5px; }
  .candy-list .btn-cart {
    padding: 4px 12px;
    cursor: pointer;
    background-color: #0073b1;
    font-weight: 800;
    color: #fff;
    text-transform: capitalize; }
  .candy-list .candy-image {
    width: 150px;
    height: 150px;
    border: 2px solid rgba(255, 255, 255, 0.4); }
  .candy-list .candy-footer {
    display: flex;
    justify-content: space-between; }

.cart {
  background-color: #fff;
  min-height: 200px;
  padding: 12px;
  box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.15), 0 4px 6px rgba(0, 0, 0, 0.2); }
  .cart tbody tr:last-child td {
    padding-bottom: 40px; }
  .cart td {
    min-width: 100px; }
  .cart .cart-title {
    font-family: -apple-system, system-ui, BlinkMacSystemFont, Segoe UI, Roboto, Helvetica Neue, Fira Sans, Ubuntu, Oxygen, Oxygen Sans, Cantarell, Droid Sans, Apple Color Emoji, Segoe UI Emoji, Segoe UI Emoji, Segoe UI Symbol, Lucida Grande, Helvetica, Arial, sans-serif;
    font-size: 18px;
    line-height: 28px;
    color: #000000e6;
    margin-bottom: 20px;
    text-align: left; }

th,
td {
  text-align: left; }

.btn-reset-cart {
  padding: 4px 12px;
  cursor: pointer;
  background-color: #900021;
  color: #fff;
  text-transform: capitalize; }

.flex {
  display: flex; }

.text-center {
  text-align: center; }

.text-left {
  text-align: left; }

/*# sourceMappingURL=candyshop.css.map */

templates.application.hbs

<section class="catalogue text-center">
  <h1 class="app-name">Welcome to the Candy Shop</h1>
  <ul class="candy-list">
    {{#each model.candies as |candy|}}
      <CandyItem
        @id={{candy.id}}
        @name={{candy.name}}
        @price={{candy.price}}
        @url={{candy.url}}
        @isOnSale={{candy.isOnSale}}
        @addToCart={{action "addToCart"}}/>
    {{/each}}
  </ul>
</section>
<section class="cart">
  <table>
    <caption class="cart-title">Shopping Cart</caption>
    <tbody>
      <tr>
        <th>Name</th>
        <th>Price</th>
        <th>Qty</th>
      </tr>
      {{#if model.cartItems.length }}
        {{#each model.cartItems as |item|}}
          <tr>
            <td class="name">{{item.name}}</td>
            <td class="price">{{item.price}}</td>
            <td class="qty">{{item.qty}}</td>
          </tr>
        {{/each}}
      {{else}}
        <tr>
          <td>cart is empty</td>
        </tr>
      {{/if}}
    </tbody>
    <tfoot>
      <tr>
        <td>Total Amount:</td>
        <td>{{totalAmount}}</td>
      </tr>
      <tr>
        <td>Total Savings:</td>
        <td>{{totalSavings}}</td>
      </tr>
      <tr>
        <td>Unique Chocolates Count:</td>
        <td>{{uniqueChocolatesCount}}</td>
      </tr>
    </tfoot>
  </table>
  {{#if model.cartItems.length }}
    <button {{action "resetCart"}} class="btn-reset-cart">Empty Cart</button>
  {{/if}}
</section>
{{outlet}}

templates.components.candy-item.hbs

<section>
  <header class="candy-name text-left">
    {{name}}
    {{#if isDiscountAllowed}}
      <button class="btn-coupon" {{action "applyCoupon"}}>use coupon</button>
    {{/if}}
  </header>
  <img src= {{url}} alt="candy image" class="rounded-border candy-image" />
  <footer class="candy-footer">
    {{#if isCouponApplied}}
      <span class="price">${{discountedPrice}}</span>
    {{else}}
      <span class="price">${{price}}</span>
    {{/if}}
    <button {{action addToCart id}} class="btn-cart">add to cart</button>
  </footer>
</section>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js"
  },
  "addons": {
		"ember-source": "3.6.0",
    "ember-data": "3.6.0",
    "ember-decorators": "2.0.0",
    "ember-cli-htmlbars": "2.0.3",
    "ember-cli-htmlbars-inline-precompile": "1.0.2"
  }
}