Vue에서 keepalive의 메모리 문제에 대해 이야기해 보겠습니다.

import Vue from 'vue'
import App from './App.vue'
import router from './router'
Vue.config.productionTip = false

new Vue({
  render: h => h(App),
  router
}).$mount('#app')

<template>
    <div>
        <div>keep-alive includeList:{{indexNameList}}</div>
        <button>新增(enter)</button> <button>删除(esc)</button> <button>强制垃圾回收(backspace)</button> <span>内存已使用<b></b></span>
        <div>
            <keep-alive>
                <router-view></router-view>
            </keep-alive>
        </div>
        <div>
            <div>
                <span>a{{index}}</span>
                <button>x</button>
            </div>
        </div>
    </div>
</template>

<script>
export default {
    name: "App",
    data() {
        return {
            indexList: [],
            usedJSHeapSize: &#39;&#39;
        }
    },
    mounted() {
        const usedJSHeapSize = document.getElementById("usedJSHeapSize")
        window.setInterval(() => {
            usedJSHeapSize.innerHTML = (performance.memory.usedJSHeapSize / 1000 / 1000).toFixed(2) + "mb"
        }, 1000)
        // 新增快捷键模拟用户实际 快速打开关闭场景
        document.onkeydown = (event) => {
            event = event || window.event;
            if (event.keyCode == 13) {//新增 
                this.routerAdd()
            } else if (event.keyCode == 27) {  //删除  
                this.routerDel() 
            } else if (event.keyCode == 8) {  //垃圾回收  
                this.gc() 
            }
        };
    },
    computed: {
        indexNameList() {
            const res = [&#39;index&#39;]//
            this.indexList.forEach(index => {
                res.push(`a${index}`)
            }) 
            return res
        }
    },
    methods: {
        routerAdd() {
            let index = 0
            this.indexList.length > 0 && (index = Math.max(...this.indexList)) 
            index++ 
            this.indexList.push(index)
            this.$router.$append(index)
            this.$router.$push(index)
        },
        routerDel(index) { 
            if (this.indexList.length == 0) return
            if(!index) {
                index = Math.max(...this.indexList)
            }  
               //每次删除都先跳回到首页, 确保删除的view 不是正在显示的view
            if (this.$route.path !== &#39;/index&#39;) { 
                this.$router.push(&#39;/index&#39;) 
            }
            let delIndex = this.indexList.findIndex((item) => item == index)
            this.$delete(this.indexList, delIndex)
            //延迟执行，加到下一个宏任务
            // setTimeout(() => {
            //     this.gc() 
            // }, 100);
        },
        routerClick(index) {
            this.$router.$push(index)
        },
        gc(){
            //强制垃圾回收 需要在浏览器启动设置 --js-flags="--expose-gc",并且不打开控制台，没有效果
            window.gc && window.gc()
        }, 
    }
};
</script>

<style>
.keepaliveBox {
    border: 1px solid red;
    padding: 3px;
}

.barBox {
    display: flex;
    flex-wrap: wrap;
}

.box {
    margin: 2px;
    min-width: 70px;
}

.box>span {
    padding: 0 2px;
    background: black;
    color: #fff;
}
</style>

<template>
    <div>首页</div>
</template>
<script>
export default {
    name:&#39;index&#39;,
}
</script>

<template>
    <div>组件view<input> </div>
</template>
<script>
export default {
    name:&#39;A&#39;,
    data(){
        return {
            a:new Array(20000000).fill(1),//大概80mb
            myname:""
        }
    },
    mounted(){  
        this.myname = this.$route.query.name
    }
}
</script>

import Vue from 'vue'
import Router from 'vue-router'
import a from '../view/a.vue'
Vue.use(Router)

const router = new Router({
    mode: 'hash', 
     routes: [
        {
            path: '/',
            redirect: '/index'
        },
        {
            path: '/index',
            component: () => import('../view/index.vue')
        }
    ]
})

//动态添加路由
router.$append = (index) => { 
    router.addRoute(`a${index}`,{
        path: `/a${index}`,
        component:  {
            ...a,
            name: `a${index}`
        },
    })  
}

router.$push = (index) => { 
        router.push({
            path:`/a${index}`,
            query:{
                name:`a${index}`
            }
        })
} 
export default  router

 a3组件.$vnode.parent.componentOptions.children[0] 引用着 a4

a2组件.$vnode.parent.componentOptions.children[0] 引用着 a3
a1组件.$vnode.parent.componentOptions.children[0] 引用着 a2
a1组件 正常，没被引用

git clone --branch 2.6.14  https://github.com/vuejs/vue.git //拉取代码

"dev": "rollup -w -c scripts/config.js --sourcemap --environment TARGET:webfull-dev",

npm run dev

module.exports = {
    chainWebpack: config => { 
      config.externals({
        vue: "Vue", 
      }); 
    },
    configureWebpack: {
      devtool: "eval-source-map"
    },
    lintOnSave: false
  };

nbsp;html>

  
    <meta>
    <meta>
    <meta>
    <link>favicon.ico">
    <title></title> 
     <!-- 这里是本地的vue源码 -->
    <script></script>
  
  
    <noscript>
    </noscript>
    <div></div>
    <!-- built files will be auto injected -->
  

/* @flow */

import { isRegExp, remove } from 'shared/util'
import { getFirstComponentChild } from 'core/vdom/helpers/index'

type CacheEntry = {
  name: ?string;
  tag: ?string;
  componentInstance: Component;
};

type CacheEntryMap = { [key: string]: ?CacheEntry };

function getComponentName (opts: ?VNodeComponentOptions): ?string {
  return opts && (opts.Ctor.options.name || opts.tag)
}

function matches (pattern: string | RegExp | Array<string>, name: string): boolean {
  if (Array.isArray(pattern)) {
    return pattern.indexOf(name) > -1
  } else if (typeof pattern === 'string') {
    return pattern.split(',').indexOf(name) > -1
  } else if (isRegExp(pattern)) {
    return pattern.test(name)
  }
  /* istanbul ignore next */
  return false
}

function pruneCache (keepAliveInstance: any, filter: Function) {
  const { cache, keys, _vnode } = keepAliveInstance
  for (const key in cache) {
    const entry: ?CacheEntry = cache[key]
    if (entry) {
      const name: ?string = entry.name
      if (name && !filter(name)) {
        pruneCacheEntry(cache, key, keys, _vnode)
      }
    }
  }
}

function pruneCacheEntry (
  cache: CacheEntryMap,
  key: string,
  keys: Array<string>,
  current?: VNode
) {
  const entry: ?CacheEntry = cache[key]
  if (entry && (!current || entry.tag !== current.tag)) {
    entry.componentInstance.$destroy()
  }
  cache[key] = null
  remove(keys, key)
}

const patternTypes: Array<function> = [String, RegExp, Array]

export default {
  name: 'keep-alive',
  abstract: true,

  props: {
    include: patternTypes,
    exclude: patternTypes,
    max: [String, Number]
  },

  methods: {
    cacheVNode() {
      const { cache, keys, vnodeToCache, keyToCache } = this
      if (vnodeToCache) {
        const { tag, componentInstance, componentOptions } = vnodeToCache
        cache[keyToCache] = {
          name: getComponentName(componentOptions),
          tag,
          componentInstance,
        }
        keys.push(keyToCache)
        // prune oldest entry
        if (this.max && keys.length > parseInt(this.max)) {
          pruneCacheEntry(cache, keys[0], keys, this._vnode)
        }
        this.vnodeToCache = null
      }
    }
  },

  created () {
    this.cache = Object.create(null)
    this.keys = []
  },

  destroyed () {
    for (const key in this.cache) {
      pruneCacheEntry(this.cache, key, this.keys)
    }
  },

  mounted () {
    this.cacheVNode()
    this.$watch('include', val => {
      pruneCache(this, name => matches(val, name))
    })
    this.$watch('exclude', val => {
      pruneCache(this, name => !matches(val, name))
    })
  },

  updated () {
    this.cacheVNode()
  },

  render () {
    const slot = this.$slots.default
    const vnode: VNode = getFirstComponentChild(slot)
    const componentOptions: ?VNodeComponentOptions = vnode && vnode.componentOptions
    if (componentOptions) {
      // check pattern
      const name: ?string = getComponentName(componentOptions)
      const { include, exclude } = this
      if (
        // not included
        (include && (!name || !matches(include, name))) ||
        // excluded
        (exclude && name && matches(exclude, name))
      ) {
        return vnode
      }

      const { cache, keys } = this
      const key: ?string = vnode.key == null
        // same constructor may get registered as different local components
        // so cid alone is not enough (#3269)
        ? componentOptions.Ctor.cid + (componentOptions.tag ? `::${componentOptions.tag}` : '')
        : vnode.key
      if (cache[key]) {
        vnode.componentInstance = cache[key].componentInstance
        // make current key freshest
        remove(keys, key)
        keys.push(key)
      } else {
        // delay setting the cache until update
        this.vnodeToCache = vnode
        this.keyToCache = key
      }

      vnode.data.keepAlive = true
    }
    return vnode || (slot && slot[0])
  }
}</function></string></string>

组件.$vnode.parent.componentOptions.children = []

  render () {
    const slot = this.$slots.default
    const vnode: VNode = getFirstComponentChild(slot) 
    
    //修复缓存列表问题
    for (const key in this.cache) {
      const entry: ?CacheEntry = this.cache[key]
      if (entry && vnode && entry.tag && entry.tag !== vnode.tag ) { //如果当前的缓存对象不为空 并且 缓存与当前加载不一样
        entry.componentInstance.$vnode.parent.componentOptions.children = []
      }
    }
   .....
}

entry.componentInstance.$vnode.parent.elm = null

  render () {
    const slot = this.$slots.default
    const vnode: VNode = getFirstComponentChild(slot) 
    
    //修复缓存列表问题
    for (const key in this.cache) {
      const entry: ?CacheEntry = this.cache[key]
      if (entry && vnode && entry.tag && entry.tag !== vnode.tag ) { //如果当前的缓存对象不为空 并且 缓存与当前加载不一样
        entry.componentInstance.$vnode.parent.componentOptions.children = []
        entry.componentInstance.$vnode.parent.elm = null
      }
    }
   .....
}