使用Vue3的watch实现数据的实时更新(附详细代码)
作者:Derlii
vue.js是一个轻量级的前端框架,你可以使用它来实现数据实时刷新,下面这篇文章主要介绍了使用Vue3的watch实现数据的实时更新的相关资料,文中通过代码介绍的非常详细,需要的朋友可以参考下
watch函数用于侦听某个值的变化,当该值发生改变后,触发对应的处理逻辑。
一、监听基础ref类型
1.监听单个ref数据
<template> <button class="style" @click="num++">增加watch</button> </template> <script setup> import { watch, ref } from "vue"; const num = ref(1); // newVal: 新值 | oldVal: 旧值 watch(num, (newVal, oldVal) => { console.log(`新值:${newVal} --- 旧值:${oldVal}`); }); </script> <style lang="scss" scoped> .style { margin: 20px 20px; } </style>
初始值为1 点击按钮后 侦听到
2.监听多个ref数据,以数组的形式侦听
<template> <h1 class="style">{{ one }} | {{ two }}</h1> <button class="style" @click="one++">增加one的值</button> <button class="style" @click="two++">增加two的值</button> </template> <script setup> import { watch, ref } from "vue"; const one = ref(0); const two = ref(10); // newVal: 新值 | oldVal: 旧值 watch([one, two], ([newVal, oldVal]) => { console.log(`新值:${newVal} --- 旧值:${oldVal}`); }); </script> <style lang="scss" scoped> .style { margin: 10px 20px; } </style>
one的初始值为1 two的初始值为10 点击one按钮后 侦听到 one的值+1
点击two按钮后 侦听到 two的值+1
3.监听一个ref对象
<template> <h1 class="style">{{ num.number }}</h1> <h1 class="style">{{ num.age }}</h1> <button class="style" @click="num.number++">增加number的值</button> </template> <script setup> import { watch,ref } from "vue"; const num = ref({ number: 1, age: 18, }); // newVal: 新值 | oldVal: 旧值 // 这个侦听器无效,即控制台无输出 watch(num, (newVal, oldVal) => { console.log("侦听器1:", newVal, oldVal); }); // getter函数形式,新旧值不一样 watch( () => ({ ...num.value }), (newVal, oldVal) => { console.log("侦听器2:", newVal, oldVal); } ); </script> <style lang="scss" scoped> .style { margin: 10px 20px; } </style>
二、监听基础reactive类型
1.监听对象中的单个属性
<template> <h1 class="style">{{ num.value }}</h1> <button class="style" @click="num.value++">增加one的值</button> </template> <script setup> import { watch, reactive } from "vue"; const num = reactive({ value: 1, }); // newVal: 新值 | oldVal: 旧值 watch( () => num.value, (newVal, oldVal) => { console.log(`新值:${newVal} --- 旧值:${oldVal}`); } ); </script> <style lang="scss" scoped> .style { margin: 10px 20px; } </style>
初始值为1 点击按钮后 侦听到
2.多层嵌套的对象
<template> <h1 class="style">{{ num.number }}|{{ num.key.age }}</h1> <button class="style" @click="num.number++">增加number的值</button> <button class="style" @click="num.key.age++">增加age的值</button> </template> <script setup> import { watch, reactive } from "vue"; const num = reactive({ number: 1, name: "张三", key: { age: 18, }, }); // newVal: 新值 | oldVal: 旧值 watch( [() => num.number, () => num.key.age], (newVal, oldVal) => { console.log(`新值:${newVal} --- 旧值:${oldVal}`); }); </script> <style lang="scss" scoped> .style { margin: 10px 20px; } </style>
number的初始值为1 点击左侧按钮number+1 age的值不变
age的初始值为18 点击右侧按钮age+1 number值不变
3.同时监听ref基本类型数据和reactive对象中的属性
<template> <h1 class="style">{{ address }}|{{ num.number }}</h1> <button class="style" @click="address++">增加address的值</button> <button class="style" @click="num.number++">增加number的值</button> </template> <script setup> import { watch, reactive, ref } from "vue"; const address = ref("88"); const num = reactive({ number: 1, name: "张三", key: { age: 18, }, }); // newVal: 新值 | oldVal: 旧值 watch([address, () => num.number], (newVal, oldVal) => { console.log(`新值:${newVal} --- 新值:${newVal}`); console.log(`旧值:${oldVal}--- 旧值:${oldVal}`); }); </script> <style lang="scss" scoped> .style { margin: 10px 20px; } </style>
address的初始值为88 点击左侧按钮address+1 number的值不变
number的初始值为1 点击右侧按钮number+1 address的值不变
总结
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