最近在看vue框架的知識，然后其中有個例子中的this的寫法讓我很疑惑
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Page Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <div id="demo"> search: <input type="text" v-model="searchName"> <ul> <li v-for="(p,index) in filterPersons" :key="index"> {{index}} --- {{p.name}} --- {{p.age}} </li> </ul> <button @click="setOrderType(1)">年齡升序</button> <button @click="setOrderType(2)">年齡降序</button> <button @click="setOrderType(0)">原本順序</button> </div> <script src="../js/vue.js"></script> <script> var vm = new Vue({ el: '#demo', data: { searchName: '', /** * 排序種類: * 0 - 原本順序 * 1 - 年齡升序 * 2 - 年齡降序 */ orderType: 0, persons: [{ name: 'Tom', age: 18 }, { name: 'Jack', age: 20 }, { name: 'Bob', age: 16 }, { name: 'Kaka', age: 25 }, { name: '22', age: 23 }, { name: '33', age: 18 }, { name: 'Shadow', age: 21 }, { name: 'Good', age: 18 }, { name: 'Lily'