9.自定义hook函数
-
什么是hook？—— 本质是一个函数，把setup函数中使用的Composition API进行了封装。
-
类似于vue2.x中的mixin。
-
自定义hook的优势: 复用代码, 让setup中的逻辑更清楚易懂。
components
Demo.vue
<template>
<h2>当前求和为：{{sum}}</h2>
<button @click="sum++">点我+1</button>
<hr>
<h2>当前点击时鼠标的坐标为：x：{{point.x}}，y：{{point.y}}</h2>
</template>
<script>
import {ref} from 'vue'
import usePoint from '../hooks/usePoint'
export default {
name: 'Demo',
setup(){
//数据
let sum = ref(0)
let point = usePoint()
//返回一个对象（常用）
return {sum,point}
}
}
</script>
Test.vue
<template>
<h2>我是Test组件</h2>
<h2>当前点击时鼠标的坐标为：x：{{point.x}}，y：{{point.y}}</h2>
</template>
<script>
import usePoint from '../hooks/usePoint'
export default {
name:'Test',
setup(){
const point = usePoint()
return {point}
}
}
</script>
hooks
usePoint.js
import {reactive,onMounted,onBeforeUnmount} from 'vue'
export default function (){
//实现鼠标“打点”相关的数据
let point = reactive({
x:0,
y:0
})
//实现鼠标“打点”相关的方法
function savePoint(event){
point.x = event.pageX
point.y = event.pageY
console.log(event.pageX,event.pageY)
}
//实现鼠标“打点”相关的生命周期钩子
onMounted(()=>{
window.addEventListener('click',savePoint)
})
onBeforeUnmount(()=>{
window.removeEventListener('click',savePoint)
})
return point
}
App.vue
<template>
<button @click="isShowDemo = !isShowDemo">切换隐藏/显示</button>
<Demo v-if="isShowDemo"/>
<hr>
<Test/>
</template>
<script>
import {ref} from 'vue'
import Demo from './components/Demo'
import Test from './components/Test'
export default {
name: 'App',
components:{Demo,Test},
setup() {
let isShowDemo = ref(true)
return {isShowDemo}
}
}
</script>
main.js
//引入的不再是Vue构造函数了，引入的是一个名为createApp的工厂函数
import { createApp } from 'vue'
import App from './App.vue'
//创建应用实例对象——app(类似于之前Vue2中的vm，但app比vm更“轻”)
const app = createApp(App)
//挂载
app.mount('#app')