vue2和vue3的v-if与v-for优先级对比学习

const todoList = [
 {
 id: 0,
 task: '吃饭',
 done: true,
 },
 {
 id: 1,
 task: '睡觉',
 done: false,
 },
 {
 id: 2,
 task: '洗澡',
 done: true,
 },
 // ...,
];

<ul>
 <!-- vue2中，v-for优先级高于v-if -->
 <li v-for="item in todoList" v-if="!item.done" :class="{todo: !item.done}" :key="item.id">
 <span>{{item.task}}</span>
 </li>
</ul>

<ul>
 <li v-for="item in todoList" v-if="item.done" :class="{finished: item.done}" :key="item.id">
 <span>{{item.task}}</span>
 </li>
</ul>

<ul>
 <template v-for="item in list" :key="item.id">
 <li v-if="!item.done" :class="{todo: !item.done}">
  <span>{{item.task}}</span>
 </li>
 </template>
</ul>
<ul>
 <template v-for="item in list" :key="item.id">
 <li v-if="item.done" :class="{finished: item.done}">
  <span>{{item.task}}</span>
 </li>
 </template>
</ul>

<div id="app">
 <!-- 最佳实践 -->
 <ul class="todo-list">
 <li v-for="item in todos" class="todo" :key="item.id">
  <span>{{item.task}}</span>
 </li>
 </ul>

 <ul v-if="showFinished">
 <li v-for="item in finished" :key="item.id" class="finished">
  <span>{{item.task}}</span>
 </li>
 </ul>

 <p>
 show finished？
 <input type="checkbox" v-model="showFinished" />
 {{showFinished ? 'yes' : 'no'}}
 </p>
</div>

// vue3.x
Vue.createApp({
 data() {
 return {
  msg: 'Todo List',
  showFinished: true,
  list: todoList,
 };
 },
 computed: {
 finished() {
  return todoList.filter(t => t.done);
 },
 todos() {
  return todoList.filter(t => !t.done);
 },
 },
}).mount('#app');

// vue2.x
new Vue({
 el: '#app',
 data() {
 return {
  msg: 'Todo List',
  showFinished: true,
  list: todoList,
 };
 },
 computed: {
 finished() {
  return todoList.filter(t => t.done);
 },
 todos() {
  return todoList.filter(t => !t.done);
 },
 },
});