How to use routing to implement page refresh and cache control in a Vue project?

How to use routing to implement page refresh and cache control in a Vue project?

In Vue project development, it is a very common requirement to use routing to implement page refresh and cache control. This article will introduce how to use routing to implement page refresh and cache control in Vue projects, and give corresponding code examples.

1. Routing configuration

First of all, you need to use vue-router for routing configuration in the Vue project. vue-router can be installed through npm and introduced and configured in main.js.

import VueRouter from 'vue-router'
import Vue from 'vue'

Vue.use(VueRouter)

const routes = [
  {
    path: '/',
    name: 'Home',
    component: () => import('@/views/Home.vue')
  },
  {
    path: '/about',
    name: 'About',
    component: () => import('@/views/About.vue')
  },
  // ...
]

const router = new VueRouter({
  mode: 'history',
  base: process.env.BASE_URL,
  routes
})

export default router

In the above code, vue-router is used through the Vue.use() method and a routing table (routes) is defined. Specific routing information can be configured according to actual needs. In addition, the routing mode is specified as history mode through the mode attribute, so that it can be accessed directly using the normal url path.

2. Page refresh

When we click the refresh button in the application or press the F5 key, the page will be refreshed. However, in SPA (Single Page Application), directly refreshing the page will cause the page state to be lost. Because Vue is based on virtual DOM, the entire application will be re-rendered every time the page is refreshed.

If we want to be able to restore to the previous state after the page is refreshed, we can achieve this by using routing in the Vue project. The specific method is to save the status of the current page to sessionStorage or localStorage, and then retrieve and restore it after the page is refreshed.

// 在App.vue中添加如下代码
beforeMount() {
  // 判断是否是刷新操作
  if (!performance.navigation.type) {
    // 获取之前保存的状态
    const state = sessionStorage.getItem('state')
    if (state) {
      // 恢复之前的状态
      this.$store.replaceState(JSON.parse(state))
    } else {
      // 第一次访问，保存当前状态
      sessionStorage.setItem('state', JSON.stringify(this.$store.state))
    }
  }
},
beforeDestroy() {
  // 刷新前保存当前的状态
  sessionStorage.setItem('state', JSON.stringify(this.$store.state))
}

In the above code, the beforeMount() and beforeDestroy() life cycle hook functions are used to determine whether it is a refresh operation. If so, the previously saved state is obtained from sessionStorage and restored to Vue's state management. in a container (such as Vuex).

3. Cache Control

In some cases, we want to be able to retain the state of the previous page when switching pages instead of re-rendering each time. This can be achieved through the keep-alive component of vue-router.

<template>
  <div>
    <keep-alive>
      <router-view v-if="$route.meta.cache" />
    </keep-alive>
    <router-view v-if="!$route.meta.cache" />
  </div>
</template>

<script>
export default {
  name: 'App',
  beforeRouteUpdate(to, from, next) {
    // 判断是否需要缓存页面
    if (to.meta.cache) {
      // 设置页面的缓存状态
      this.$children.forEach(child => {
        if (child.$vnode && child.$vnode.data.keepAlive) {
          child.$vnode.parent.componentInstance.cache[child.$vnode.key] = child;
        }
      })
      next()
    } else {
      // 清除之前缓存的页面状态
      this.$children.forEach(child => {
        if (child.$vnode && child.$vnode.data.keepAlive) {
          if (child.$vnode.parent.componentInstance.cache[child.$vnode.key]) {
            delete child.$vnode.parent.componentInstance.cache[child.$vnode.key];
          }
        }
      })
      next()
    }
  }
}
</script>

In the above code, the page is cached through the keep-alive component, and the router-view element is used to display the corresponding page according to the routing configuration. At the same time, the cache status of the page is controlled by setting the meta field of the route.

In the beforeRouteUpdate() method, determine whether the page needs to be cached, and set the cache status of the page. At the same time, clear the previously cached page status when switching pages.

Through the above code examples, we can implement page refresh and cache control functions in the Vue project to improve user experience and application performance. Of course, the specific implementation method can be adjusted and expanded according to project needs. I hope this article will help you use routing to implement page refresh and cache control in your Vue project.

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