第一种方法

onActivated + onBeforeRouteLeave 方法实现

1.思路

• 页面首先要是缓存的组件实例 keep-alive
• 用onActivated 才能将滚动位置 缓存起来
• 每次进入都要将存储的位置重新赋值给页面
• 路由守卫 beforeRouteLeave路由离开前记录当前的位置

import { onBeforeRouteLeave} from 'vue-router'

const scrollRef = ref(null)
const scrollTop = ref(0)

onActivated(()=>{
  nextTick(()=>{
    scrollRef.value.scrollTop = scrollTop .value
  })
})
onBeforeRouteLeave((to, from, next)=>{
  scrollTop .value = scrollRef.value.scrollTop
  next()
})

<div class="mall-page" ref="scrollRef" >
  ......
<div>
.mall-page{
  background: #FFFFFF;
  overflow: auto; 
  height: 100vh;
 }

第二种

事件监听 + vuex存储或者本地存储都行

1.思路

• 监听页面最外层div滚动事件,将当前的位置存储起来
• 不断滚动，不断记录需要对函数限制执行频率
• 销毁时需移除监听

import { debounce } from 'throttle-debounce' //限制函数的执行频率
import { ref, onActivated, nextTick, onMounted, onUnmounted } from 'vue'

const scrollRef = ref(null)
onActivated(()=>{
  nextTick(()=>{
    scrollRef.value.scrollTop =  localStorage.getItem("scrollTop")
  })
})

onMounted(()=>{
   scrollRef.value.addEventListener('scroll', handle_Scroll.bind(this))
})

onUnmounted(()=>{
  scrollRef.value.removeEventListener('scroll', handle_Scroll.bind(this))
})
const handle_Scroll = debounce(100, function (e) {
    localStorage.setItem("scrollTop",scrollRef.value.scrollTop) 
})

<div class="mall-page" ref="scrollRef" >
  ......
<div>
.mall-page{
  background: #FFFFFF;
  overflow: auto;
  height: 100vh; // 一定要设置高度才会滚动
   }