一文快速详解前端框架 Vue 最强大的功能

//App.vue父组件
<template>
<div id="app">
<users v-bind:users="users"></users>//前者自定义名称便于子组件调用，后者要传递数据名
</div>
</template>
<script> import Users from "./components/Users" export default { name: 'App', data(){ return{  users:["Henry","Bucky","Emily"] } }, components:{ "users":Users } } //users子组件 <template> <div class="hello"> <ul> <li v-for="user in users">{{user}}</li>//遍历传递过来的值，然后呈现到页面 </ul> </div> </template> <script> export default { name: 'HelloWorld', props:{  users:{   //这个就是父组件中子标签自定义名字  type:Array,  required:true } } } </script>

// 子组件
<template>
<header>
<h1 @click="changeTitle">{{title}}</h1>//绑定一个点击事件
</header>
</template>
<script> export default { name: 'app-header', data() { return {  title:"Vue.js Demo" } }, methods:{  changeTitle() { this.$emit("titleChanged","子向父组件传值");//自定义事件 传递值“子向父组件传值” } } } </script>
// 父组件
<template>
<div id="app">
<app-header v-on:titleChanged="updateTitle" ></app-header>//与子组件titleChanged自定义事件保持一致
// updateTitle($event)接受传递过来的文字
<h2>{{title}}</h2>
</div>
</template>
<script> import Header from "./components/Header" export default { name: 'App', data(){ return{  title:"传递的是一个值" } }, methods:{  updateTitle(e){ //声明这个函数 this.title = e; } }, components:{ "app-header":Header, } } </script>

var Event=new Vue();
Event.$emit(事件名,数据);
Event.$on(事件名,data => {});

<div id="itany">
<my-a></my-a>
<my-b></my-b>
<my-c></my-c>
</div>
<template id="a">
<div>
<h3>A组件：{{name}}</h3>
<button @click="send">将数据发送给C组件</button>
</div>
</template>
<template id="b">
<div>
<h3>B组件：{{age}}</h3>
<button @click="send">将数组发送给C组件</button>
</div>
</template>
<template id="c">
<div>
<h3>C组件：{{name}}，{{age}}</h3>
</div>
</template>
<script> var Event = new Vue();//定义一个空的Vue实例 var A = {  template: '#a',  data() { return {   name: 'tom' } },  methods: {  send() { Event.$emit('data-a', this.name); } } } var B = {  template: '#b',  data() { return {   age: 20 } },  methods: {  send() { Event.$emit('data-b', this.age); } } } var C = {  template: '#c',  data() { return {   name: '',   age: "" } },  mounted() {//在模板编译完成后执行 Event.$on('data-a',name => { this.name = name;//箭头函数内部不会产生新的this，这边如果不用=>,this指代Event }) Event.$on('data-b',age => { this.age = age; }) } } var vm = new Vue({  el: '#itany',  components: { 'my-a': A, 'my-b': B, 'my-c': C } }); 
 </script>

let defaultCity = "上海"
try { // 用户关闭了本地存储功能，此时在外层加个try...catch
if (!defaultCity){
 defaultCity = JSON.parse(window.localStorage.getItem('defaultCity'))
}
}catch(e){}
export default new Vuex.Store({
 state: {
 city: defaultCity
},
 mutations: {
 changeCity(state, city) {
  state.city = city
try {
  window.localStorage.setItem('defaultCity', JSON.stringify(state.city));
// 数据改变的时候把数据拷贝一份保存到localStorage里面
} catch (e) {}
}
}
})

JSON.stringify(state.subscribeList); // array -> string
JSON.parse(window.localStorage.getItem("subscribeList")); // string -> array 

// index.vue
<template>
<div>
<h2>浪里行舟</h2>
<child-com1 :foo="foo" :boo="boo" :coo="coo" :doo="doo"  title="前端工匠" ></child-com1>
</div>
</template>
<script> const childCom1 = () => import("./childCom1.vue"); export default { components: { childCom1 }, data() { return {  foo: "Javascript",  boo: "Html",  coo: "CSS",  doo: "Vue" }; } }; </script>
// childCom1.vue
<template class="border">
<div>
<p>foo: {{ foo }}</p>
<p>childCom1的$attrs: {{ $attrs }}</p>
<child-com2 v-bind="$attrs"></child-com2>
</div>
</template>
<script> const childCom2 = () => import("./childCom2.vue"); export default { components: {  childCom2 }, inheritAttrs: false, // 可以关闭自动挂载到组件根元素上的没有在props声明的属性 props: {  foo: String // foo作为props属性绑定 }, created() {  console.log(this.$attrs); // { "boo": "Html", "coo": "CSS", "doo": "Vue", "title": "前端工匠" } } }; </script>
// childCom2.vue
<template>
<div class="border">
<p>boo: {{ boo }}</p>
<p>childCom2: {{ $attrs }}</p>
<child-com3 v-bind="$attrs"></child-com3>
</div>
</template>
<script> const childCom3 = () => import("./childCom3.vue"); export default { components: {  childCom3 }, inheritAttrs: false, props: {  boo: String }, created() {  console.log(this.$attrs); // { "boo": "Html", "coo": "CSS", "doo": "Vue", "title": "前端工匠" } } }; </script>
// childCom3.vue
<template>
<div class="border">
<p>childCom3: {{ $attrs }}</p>
</div>
</template>
<script> export default { props: {  coo: String,  title: String } }; </script>

// A.vue
export default {
 provide: {
 name: '浪里行舟'
}
}
// B.vue
export default {
 inject: ['name'],
 mounted () {
 console.log(this.name); // 浪里行舟
}
}

// A 组件 
<div>
  <h1>A 组件</h1>
  <button @click="() => changeColor()">改变color</button>
  <ChildrenB />
  <ChildrenC />
</div>
......
 data() {
 return {
  color: "blue"
 };
 },
 // provide() {
 // return {
 //  theme: {
 //  color: this.color //这种方式绑定的数据并不是可响应的
 //  } // 即A组件的color变化后，组件D、E、F不会跟着变
 // };
 // },
 provide() {
 return {
  theme: this//方法一：提供祖先组件的实例
 };
 },
 methods: {
 changeColor(color) {
  if (color) {
  this.color = color;
  } else {
  this.color = this.color === "blue" ? "red" : "blue";
  }
 }
 }
 // 方法二:使用2.6最新API Vue.observable 优化响应式 provide
 // provide() {
 // this.theme = Vue.observable({
 //  color: "blue"
 // });
 // return {
 //  theme: this.theme
 // };
 // },
 // methods: {
 // changeColor(color) {
 //  if (color) {
 //  this.theme.color = color;
 //  } else {
 //  this.theme.color = this.theme.color === "blue" ? "red" : "blue";
 //  }
 // }
 // }
// F 组件 
<template functional>
 <div class="border2">
 <h3 :style="{ color: injections.theme.color }">F 组件</h3>
 </div>
</template>
<script> export default { inject: {  theme: {  //函数式组件取值不一样  default: () => ({})  } } }; </script>

// component-a 子组件
export default {
 data () {
return {
  title: 'Vue.js'
}
},
 methods: {
 sayHello () {
  window.alert('Hello');
}
}
}
// 父组件
<template>
<component-a ref="comA"></component-a>
</template>
<script>
export default {
 mounted () {
const comA = this.$refs.comA;
  console.log(comA.title); // Vue.js
  comA.sayHello(); // 弹窗
}
}
</script>

// parent.vue
<component-a></component-a>
<component-b></component-b>
<component-b></component-b>