GRWQEgZ

grwqegz.markdown

GRWQEgZ

A Pen by Edward Lance Lorilla on CodePen.

License.

index.html

 <div id="app" v-cloak>
   <div v-if="books.length">
     <table>
       <thead>
         <tr>
           <th></th>
           <th>Book name</th>
           <th>Publication date</th>
           <th>Price</th>
           <th>Purchase quantity</th>
           <th>Delete</th>
         </tr>
       </thead>
       <tbody>
         <tr v-for="(item,index) in books">
           <th>{{item.id}}</th>
           <th>{{item.name}}</th>
           <th>{{item.date}}</th>
           <!--Scheme 1 Keep the decimal point and currency symbol-->
           <!-- <th>{{"$"+item.price.toFixed(2)}}</th> -->
           <!--Scheme Two-->
           <!-- <th>{{getFinalPrice(item.price)}}</th> -->
           <!--Plan Three-->
           <th>{{item.price | showPrice}}</th>
           <th>
             <button @click="decrement(index)" :disabled="item.count<=0">-</button>
             {{item.count}}
             <button @click="increment(index)">+</button>
           </th>
           <th><button @click="removeHandle(index)">Remove</button></th>
         </tr>
       </tbody>
     </table>
     <h2>Total price: {{totalPrice | showPrice}}</h2>
   </div>
   <h2 v-else>
     Shopping cart is empty
   </h2>
</div>

script.js

const app = new Vue({
  el:"#app",
  data:{
    books:[
      {
        id:1,
        name:"Introduction to Algorithms",
        date:'2006-9',
        price: 85.00,
        count:1
      },
      {
        id:2,
        name:"UNIX Programming Art",
        date:'2006-2',
        price: 50.00,
        count:1
      },
      {
        id:3,
        name:"Programming Art",
        date:'2008-10',
        price:39.00,
        count:1
      },
      {
        id:4,
        name:"Code Encyclopedia",
        date:'2006-3',
        price:128.00,
        count:1
      },
      ]
  },
  methods: {
    //Here we abandon the use of methods to find the total price, and instead use calculated attributes because it is more efficient.
    // getFinalPrice(price){
    // return "￥"+price.toFixed(2)
    // },
    increment(index){
      this.books[index].count++
    },
    decrement(index){
      this.books[index].count--
    },
    removeHandle(index){
      this.books.splice(index,1);
    }
    
  },
  computed: {
    totalPrice(){
      // Option 1: Ordinary for loop
      // let totalPrice = 0;
      // for(let i=0;i<this.books.length;i++){
      // totalPrice += this.books[i].price * this.books[i].count
      //}
      // return totalPrice
      
      // Option 2: for in
      // let totalPrice = 0;
      // for(let i in this.books){
      // // console.log(i);//1 2 3 4
      // totalPrice += this.books[i].price * this.books[i].count
      //}
      // return totalPrice
      
      // Option 3: for of
      // let totalPrice = 0;
      // for(let item of this.books){
      // // console.log(item);//What you get here is each object in the array
      // totalPrice += item.price * item.count
      //}
      // return totalPrice
      
      // Option 4: reduce
      return this.books.reduce(function (preValue, book) {
        // console.log(book);//output four objects separately
        return preValue + book.price * book.count
      }, 0)
    }
  },
  // filter
  filters:{
    showPrice(price){
      return "$"+price.toFixed(2)
    }
  }
})

scripts

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.6.11/vue.min.js"></script>

style.css

table{
  border: 1px solid #e9e9e9;
  border-collapse: collapse;
  border-spacing: 0;
}
th,td{
  padding: 8px 16px;
  border: 1px solid #e9e9e9;
  text-align: center;
}
th{
  background-color: #f7f7f7;
  color: #5c6b77;
  font-weight: 600;
}
[v-cloak]{
  display: none;
}