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Atguigu---17-life cycle

2022-06-25 09:04:00 【Zhangshao】

Life cycle introduction 

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title> Lead to the life cycle </title>
		<!--  introduce Vue -->
		<script type="text/javascript" src="../js/vue.js"></script>
	</head>
	<body>
		<!--  Life cycle ： 1. also called ： Life cycle callback function 、 Life cycle function 、 Lifecycle hook . 2. What is it? ：Vue Some special named functions that help us call at the critical moment . 3. The name of the lifecycle function cannot be changed , But the specific content of the function is written by the programmer according to the requirements . 4. In the life cycle function this The point is vm  or   Component instance object . -->
		<!--  Prepare a container -->
		<div id="root">
			<h2 v-if="a"> How do you do </h2>
			<h2 :style="{opacity}"> Welcome to learn Vue</h2>
		</div>
	</body>

	<script type="text/javascript"> Vue.config.productionTip = false // prevent  vue  Generate production prompts at startup . new Vue({
       el:'#root', data:{
       a:false, opacity:1 }, methods: {
       }, //Vue Complete the parsing of the template and put the initial real DOM After the element is placed on the page （ The mount is finished ） call mounted mounted(){
       console.log('mounted',this) setInterval(() => {
       this.opacity -= 0.01 if(this.opacity <= 0) this.opacity = 1 },16) }, }) // Through the external timer （ Not recommended ） /* setInterval(() => { vm.opacity -= 0.01 if(vm.opacity <= 0) vm.opacity = 1 },16) */ </script>
</html>

Life cycle diagram

Insert picture description here
Analysis life cycle 

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title> Analysis life cycle </title>
		<!--  introduce Vue -->
		<script type="text/javascript" src="../js/vue.js"></script>
	</head>
	<body>
		<!--  Prepare a container -->
		<div id="root" :x="n">
			<h2 v-text="n"></h2>
			<h2> Current n The value is ：{
   {n}}</h2>
			<button @click="add"> Am I n+1</button>
			<button @click="bye"> Point I destroy vm</button>
		</div>
	</body>

	<script type="text/javascript"> Vue.config.productionTip = false // prevent  vue  Generate production prompts at startup . new Vue({
       el:'#root', // template:` // <div> // <h2> Current n The value is ：{
      {n}}</h2> // <button @click="add"> Am I n+1</button> // </div> // `, data:{
       n:1 }, methods: {
       add(){
       console.log('add') this.n++ }, bye(){
       console.log('bye') this.$destroy() } }, watch:{
       n(){
       console.log('n Changed ') } }, beforeCreate() {
       console.log('beforeCreate') }, created() {
       console.log('created') }, beforeMount() {
       console.log('beforeMount') }, mounted() {
       console.log('mounted') }, beforeUpdate() {
       console.log('beforeUpdate') }, updated() {
       console.log('updated') }, beforeDestroy() {
       console.log('beforeDestroy') }, destroyed() {
       console.log('destroyed') }, }) </script>
</html>

Summary life cycle 

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title> Lead to the life cycle </title>
		<!--  introduce Vue -->
		<script type="text/javascript" src="../js/vue.js"></script>
	</head>
	<body>
		<!--  Common life cycle hooks ： 1.mounted:  send out ajax request 、 Start timer 、 Binding custom events 、 Subscribe to news, etc 【 Initialization operation 】. 2.beforeDestroy:  Clear timer 、 Unbind custom events 、 Unsubscribe messages, etc 【 Finishing work 】.  About destruction Vue example  1. Destroy with the help of Vue Developer tools don't see any information . 2. After destruction, the custom event will become invalid , But the original DOM The event is still valid . 3. Usually not in beforeDestroy Operational data , Because even if you manipulate data , The update process will no longer be triggered . -->
		<!--  Prepare a container -->
		<div id="root">
			<h2 :style="{opacity}"> Welcome to learn Vue</h2>
			<button @click="opacity = 1"> Transparency set to 1</button>
			<button @click="stop"> Click me to stop the transformation </button>
		</div>
	</body>

	<script type="text/javascript"> Vue.config.productionTip = false // prevent  vue  Generate production prompts at startup . new Vue({
       el:'#root', data:{
       opacity:1 }, methods: {
       stop(){
       this.$destroy() } }, //Vue Complete the parsing of the template and put the initial real DOM After the element is placed on the page （ The mount is finished ） call mounted mounted(){
       console.log('mounted',this) this.timer = setInterval(() => {
       console.log('setInterval') this.opacity -= 0.01 if(this.opacity <= 0) this.opacity = 1 },16) }, beforeDestroy() {
       clearInterval(this.timer) console.log('vm I'm going to travel to the West ') }, }) </script>
</html>
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版权声明
本文为[Zhangshao]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/176/202206250736584693.html

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