如何理解Vue的render函數的具體用法

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如何理解Vue的render函數的具體用法

如何理解Vue的render函數的具體用法:本文介紹了如何理解Vue的render函數的具體用法，分享給大家，具體如下：第一個參數(必須) - {String | Object | Function} <!DOCTYPE html> <html lang=en> <head> <meta charset=UTF-8

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導讀如何理解Vue的render函數的具體用法:本文介紹了如何理解Vue的render函數的具體用法，分享給大家，具體如下：第一個參數(必須) - {String | Object | Function} <!DOCTYPE html> <html lang=en> <head> <meta charset=UTF-8

本文介紹了如何理解Vue的render函數的具體用法，分享給大家，具體如下：

第一個參數(必須) - {String | Object | Function}

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <elem></elem>
 </div>
 <script>
 Vue.component('elem', {
 render: function(createElement) {
 return createElement('div');//一個HTML標簽字符
 /*return createElement({
 template: '<div></div>'//組件選項對象
 });*/
 /*var func = function() {
 return {template: '<div></div>'}
 };
 return createElement(func());//一個返回HTML標簽字符或組件選項對象的函數*/
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

第二個參數(可選) - {Object}

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <elem></elem>
 </div>
 <script>
 Vue.component('elem', {
 render: function(createElement) {
 var self = this;
 return createElement('div', {//一個包含模板相關屬性的數據對象
 'class': {
 foo: true,
 bar: false
 },
 style: {
 color: 'red',
 fontSize: '14px'
 },
 attrs: {
 id: 'foo'
 },
 domProps: {
 innerHTML: 'baz'
 }
 });
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

第三個參數(可選) - {String | Array}

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <elem></elem>
 </div>
 <script>
 Vue.component('elem', {
 render: function(createElement) {
 var self = this;
 // return createElement('div', '文本');//使用字符串生成文本節點
 return createElement('div', [//由createElement函數構建而成的數組
 createElement('h1', '主標'),//createElement函數返回VNode對象
 createElement('h2', '副標')
 ]);
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

兩種組件寫法對比

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <ele></ele>
 </div>
 <script>
 /*Vue.component('ele', {
 template: '<div id="elem" :class="{show: show}" @click="handleClick">文本</div>',
 data: function() {
 return {
 show: true
 }
 },
 methods: {
 handleClick: function() {
 console.log('clicked!');
 }
 }
 });*/
 Vue.component('ele', {
 render: function(createElement) {
 return createElement('div', {
 'class': {
 show: this.show
 },
 attrs: {
 id: 'elem'
 },
 on: {
 click: this.handleClick
 }
 }, '文本');
 },
 data: function() {
 return {
 show: true
 }
 },
 methods: {
 handleClick: function() {
 console.log('clicked!');
 }
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

this.$slots用法

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <blog-post>
 <h1 slot="header"><span>About Me</span></h1>
 <p>Here's some page content</p>
 <p slot="footer">Copyright 2016 Evan You</p>
 <p>If I have some content down here</p>
 </blog-post>
 </div>
 <script>
 Vue.component('blog-post', {
 render: function(createElement) {
 var header = this.$slots.header,//返回由VNode組成的數組
 body = this.$slots.default,
 footer = this.$slots.footer;
 return createElement('div', [
 createElement('header', header),
 createElement('main', body),
 createElement('footer', footer)
 ])
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

使用props傳遞數據

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <ele :show="show"></ele>
 <ele :show="!show"></ele>
 </div>
 <script>
 Vue.component('ele', {
 render: function(createElement) {
 if (this.show) {
 return createElement('p', 'true');
 } else {
 return createElement('p', 'false');
 }
 },
 props: {
 show: {
 type: Boolean,
 default: false
 }
 }
 });
 new Vue({
 el: '#app',
 data: {
 show: false
 }
 });
 </script>
</body>
</html>

VNodes必須唯一

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <!-- VNode必須唯一 -->
 <div id="app">
 <ele></ele>
 </div>
 <script>
 var child = {
 render: function(createElement) {
 return createElement('p', 'text');
 }
 };
 /*Vue.component('ele', {
 render: function(createElement) {
 var childNode = createElement(child);
 return createElement('div', [
 childNode, childNode//VNodes必須唯一，渲染失敗
 ]);
 }
 });*/
 Vue.component('ele', {
 render: function(createElement) {
 return createElement('div', 
 Array.apply(null, {
 length: 2
 }).map(function() {
 return createElement(child)//正確寫法
 })
 );
 }
 });
 new Vue({
 el: '#app'
 })
 </script>
</body>
</html>

v-model指令

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <el-input :name="name" @input="val=>name=val"></el-input>
 <div>你的名字是{{name}}</div>
 </div>
 <script>
 Vue.component('el-input', {
 render: function(createElement) {
 var self = this;
 return createElement('input', {
 domProps: {
 value: self.name
 },
 on: {
 input: function(event) {
 self.$emit('input', event.target.value);
 }
 }
 })
 },
 props: {
 name: String
 }
 });
 new Vue({
 el: '#app',
 data: {
 name: 'hdl'
 }
 });
 </script>
</body>
</html>

作用域插槽

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <ele>
 <template scope="props">
 <span>{{props.text}}</span>
 </template>
 </ele>
 </div>
 <script>
 Vue.component('ele', {
 render: function(createElement) {
 // 相當于<div><slot :text="msg"></slot></div>
 return createElement('div', [
 this.$scopedSlots.default({
 text: this.msg
 })
 ]);
 },
 data: function() {
 return {
 msg: '來自子組件'
 }
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

向子組件中傳遞作用域插槽

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <ele></ele>
 </div>
 <script>
 Vue.component('ele', {
 render: function(createElement) {
 return createElement('div', [
 createElement('child', {
 scopedSlots: {
 default: function(props) {
 return [
 createElement('span', '來自父組件'),
 createElement('span', props.text)
 ];
 }
 }
 })
 ]);
 }
 });
 Vue.component('child', {
 render: function(createElement) {
 return createElement('b', this.$scopedSlots.default({text: '我是組件'}));
 }
 });
 new Vue({
 el: '#app'
 });
 </script>
</body>
</html>

函數化組件

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>render</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 <smart-item :data="data"></smart-item>
 <button @click="change('img')">切換為圖片為組件</button>
 <button @click="change('video')">切換為視頻為組件</button>
 <button @click="change('text')">切換為文本組件</button>
 </div>
 <script>
 // 圖片組件選項
 var ImgItem = {
 props: ['data'],
 render: function(createElement) {
 return createElement('div', [
 createElement('p', '圖片組件'),
 createElement('img', {
 attrs: {
 src: this.data.url
 }
 })
 ]);
 }
 }
 // 視頻組件
 var VideoItem = {
 props: ['data'],
 render: function(createElement) {
 return createElement('div', [
 createElement('p', '視頻組件'),
 createElement('video', {
 attrs: {
 src: this.data.url,
 controls: 'controls',
 autoplay: 'autoplay'
 }
 })
 ]);
 }
 };
 /*純文本組件*/
 var TextItem = {
 props: ['data'],
 render: function(createElement) {
 return createElement('div', [
 createElement('p', '純文本組件'),
 createElement('p', this.data.text)
 ]);
 }
 };

 Vue.component('smart-item', {
 functional: true,
 render: function(createElement, context) {
 function getComponent() {
 var data = context.props.data;
 if (data.type === 'img') return ImgItem;
 if (data.type === 'video') return VideoItem;
 return TextItem;
 }
 return createElement(
 getComponent(),
 {
 props: {
 data: context.props.data
 }
 },
 context.children
 )
 },
 props: {
 data: {
 type: Object,
 required: true
 }
 }
 });
 new Vue({
 el: '#app',
 data() {
 return {
 data: {}
 }
 },
 methods: {
 change: function(type) {
 if (type === 'img') {
 this.data = {
 type: 'img',
 url: 'https://raw.githubusercontent.com/iview/iview/master/assets/logo.png'
 }
 } else if (type === 'video') {
 this.data = {
 type: 'video',
 url: 'http://vjs.zencdn.net/v/oceans.mp4'
 }
 } else if (type === 'text') {
 this.data = {
 type: 'text',
 content: '這是一段純文本'
 }
 }
 }
 },
 created: function() {
 this.change('img');
 }
 });
 </script>
</body>
</html>

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如何理解Vue的render函數的具體用法

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如何理解Vue的render函數的具體用法

如何理解Vue的render函數的具體用法

如何理解Vue的render函數的具體用法

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