Vue 監聽元素前後變化值例項
阿新 • • 發佈:2020-07-30
我就廢話不多說了,大家還是直接看程式碼吧~
export default { data() { return { item: '' } },watch: { item(now,before){ let remove = before.filter(x => now.indexOf(x) == -1); let add = now.filter(x => before.indexOf(x) == -1); /* 顯示字串或陣列元素的增加和減少 */ console.log(add,remove); } } }
補充知識:Vuejs+Element監聽-window.resize-el-menu響應式顯示
效果
程式碼
template
<template> <div class="sidebar"> <!-- 摺疊按鈕 --> <div class="collapse-btn" @click="collapseChage"> <i class="el-icon-d-arrow-left" v-show="!collapse" title="收起"> <small>收縮側邊欄</small> </i> <i class="el-icon-d-arrow-right" v-show="collapse" title="展開"></i> </div> <el-menu class="sidebar-el-menu" :default-active="onRoutes" :collapse="collapse" text-color="#8d9199" active-text-color="#20a0ff" unique-opened router > <template v-for="item in items"> <template v-if="item.subs"> <el-submenu :index="item.index" :key="item.index"> <template slot="title"> <i :class="item.icon"></i> <span slot="title">{{ item.title }}</span> </template> <template v-for="subItem in item.subs"> <el-submenu v-if="subItem.subs" :index="subItem.index" :key="subItem.index"> <template slot="title"> <i :class="subItem.icon"></i> {{ subItem.title }} </template> <el-menu-item v-for="(threeItem,i) in subItem.subs" :key="i" :index="threeItem.index" >{{ threeItem.title }}</el-menu-item> </el-submenu> <el-menu-item v-else :index="subItem.index" :key="subItem.index"> <i :class="subItem.icon"></i> {{ subItem.title }} </el-menu-item> </template> </el-submenu> </template> <template v-else> <el-menu-item :index="item.index" :key="item.index"> <i :class="item.icon"></i> <span slot="title">{{ item.title }}</span> </el-menu-item> </template> </template> </el-menu> <div> <i class="el-icon-d-arrow-right" v-show="collapse" title="展開"></i> </div> </div> </template>
javascript
<script> import bus from "./bus"; import { menu } from "../../data/menu"; export default { data() { return { collapse: false,items: menu,screenWidth: 1000 }; },computed: { onRoutes() { return this.$route.path.replace("/",""); } },created() { // 通過 Event Bus 進行元件間通訊,來摺疊側邊欄 bus.$on("collapse",msg => { this.collapse = msg; }); },mounted() { // if (document.body.clientWidth < 1500) { // this.collapseChage(); // } const that = this; window.addEventListener("resize",function() { return (() => { window.screenWidth = document.body.clientWidth; that.screenWidth = window.screenWidth; })(); }); },watch: { screenWidth(val) { if (!this.timer) { this.screenWidth = val; this.timer = true; let that = this; setTimeout(function() { // that.screenWidth = that.$store.state.canvasWidth console.log(that.screenWidth); that.auto(); that.timer = false; },400); } } },methods: { // 側邊欄摺疊 collapseChage() { this.collapse = !this.collapse; bus.$emit("collapse",this.collapse); },auto() { if (this.screenWidth < 1200) { console.log("收起來"); this.collapse = true; bus.$emit("collapse",true); } else { console.log("展開"); this.collapse = false; bus.$emit("collapse",false); } } } }; </script>
css
<style scoped> .sidebar { z-index: 1024; display: block; position: fixed; left: 0; top: 70px; bottom: 0; overflow-y: scroll; } .sidebar::-webkit-scrollbar { width: 0; } .sidebar-el-menu:not(.el-menu--collapse) { width: 200px; } .sidebar > ul { height: 100%; /*寫給不支援calc()的瀏覽器*/ height: calc(100% - 52px); top: 30px; background-color: rgb(235,239,243); border-top: 1px solid #d6d6d6; } .sidebar > ul > li,.sidebar > ul > li div { background-color: rgb(235,243); } .sidebar > ul > li > ul { background-color: rgb(235,243); } .el-menu { background-color: rgb(235,243); } i { margin-right: 10px; } .collapse-btn { height: 30px; width: 100%; cursor: pointer; line-height: 30px; position: absolute; top: 0; left: 0; background-color: #f4f6fa; color: #fff; text-align: center; overflow: hidden; box-sizing: border-box; box-shadow: 0 5px 10px #ddd; } .collapse-btn i { color: #8d9199; padding: 1px; cursor: pointer; overflow: hidden; text-overflow: ellipsis; } /* .collapse-btn:before{ content: ""; display: block; height: 0; border-top: 1px dotted #909399; position: absolute; left: 15px; right: 15px; top: 18px; } */ </style>
##注意⚠️
此開發框架是github 名為 lin-xin 的 vue-manage-system
因公司專案需要相容iPad,故而修改
詳細程式碼點選這裡
以上這篇Vue 監聽元素前後變化值例項就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支援我們。