<!--
1. 列表顯示
  陣列: v-for / index

<h2>測試: v-for 遍歷陣列</h2>
<ul>
  <li v-for="(p, index) in persons" :key="index">
    {{index}}--{{p.name}}--{{p.age}}

  </li>
</ul>

  物件: v-for / key

<h2>測試: v-for 遍歷物件</h2>

<ul>
  <li v-for="(item, key) in persons[1]" :key="key">{{key}}={{item}}</li>
 
</ul>

<button @click="addP({name: 'xfzhang', age: 18})">新增</button>

2. 列表的更新顯示
  刪除item

    --<button @click="deleteP(index)">刪除</button>

  替換item

    --<button @click="updateP(index, {name:'Cat', age: 16})">更新</button>

-->

<script type="text/javascript" src="../js/vue.js"></script>
 
<script type="text/javascript">
  new Vue({
    el: '#demo',
    data: {
      persons: [
        {name: 'Tom', age:18},
        {name: 'Jack', age:17},
        {name: 'Bob', age:19},
        {name: 'Mary', age:16}
      ]
    },

    methods: {
      deleteP (index) {
        this.persons.splice(index, 1) // 呼叫了不是原生陣列的splice(), 而是一個變異(重寫)方法
 
              // 1. 呼叫原生的陣列的對應方法
              // 2. 更新介面
      },

      updateP (index, newP) {
        console.log('updateP', index, newP)
        // this.persons[index] = newP  // vue根本就不知道
        this.persons.splice(index, 1, newP)
        // this.persons = []
      },

      addP (newP) {
        this.persons.push(newP)
      }
    }
  })