实现一个功能，点击按钮，实现两个标签的切换显示隐藏：
代码一：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Vue v-once 指令</title>
<script src="./vue.js"></script>
<style>
</style>
</head>
<body>
<div id="root">
<child-one v-if="type === 'child-one'"></child-one>
<child-two v-if="type === 'child-two'"></child-two>
<button @click="handleBtnClick">切换</button>
</div>
<script>
Vue.component('child-one', {
template: '<div>child-one</div>'
})
Vue.component('child-two', {
template: '<div>child-two</div>'
})
var app = new Vue({
el: " #root ",
data: {
type: 'child-one'
},
methods: {
handleBtnClick: function() {
this.type = this.type === 'child-one' ? 'child-two' : 'child-one'
}
}
})
</script>
</body>
</html>代码二：可以改成用动态组件<component :is="type"></component>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Vue v-once 指令</title>
<script src="./vue.js"></script>
<style>
</style>
</head>
<body>
<div id="root">
<component :is="type"></component>
<button @click="handleBtnClick">切换</button>
</div>
<script>
Vue.component('child-one', {
template: '<div>child-one</div>'
})
Vue.component('child-two', {
template: '<div>child-two</div>'
})
var app = new Vue({
el: " #root ",
data: {
type: 'child-one'
},
methods: {
handleBtnClick: function() {
this.type = this.type === 'child-one' ? 'child-two' : 'child-one'
}
}
})
</script>
</body>
</html>代码三、使用v-once
使用到缓存，有效提高性能，不用频繁销毁元素。完整代码如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Vue v-once 指令</title>
<script src="./vue.js"></script>
<style>
</style>
</head>
<body>
<div id="root">
<component :is="type"></component>
<button @click="handleBtnClick">切换</button>
</div>
<script>
Vue.component('child-one', {
template: '<div v-once>child-one</div>'
})
Vue.component('child-two', {
template: '<div v-once>child-two</div>'
})
var app = new Vue({
el: " #root ",
data: {
type: 'child-one'
},
methods: {
handleBtnClick: function() {
this.type = this.type === 'child-one' ? 'child-two' : 'child-one'
}
}
})
</script>
</body>
</html>