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

<keep-alive include="a">
 <component></component>
</keep-alive>

<keep-alive exclude="a">
 <component></component>
</keep-alive>

props: {
 include: patternTypes,
 exclude: patternTypes,
 max: [String, Number]
},
created () {
 // 創(chuàng)建緩存對象
 this.cache = Object.create(null)
 // 創(chuàng)建一個key別名數組(組件name)
 this.keys = []
},

destroyed () {
 /* 遍歷銷毀所有緩存的組件實例*/
 for (const key in this.cache) {
  pruneCacheEntry(this.cache, key, this.keys)
 }
},

render () {
 /* 獲取插槽 */
 const slot = this.$slots.default
 /* 根據插槽獲取第一個組件組件 */
 const vnode: VNode = getFirstComponentChild(slot)
 const componentOptions: ?VNodeComponentOptions = vnode && vnode.componentOptions
 if (componentOptions) {
 // 獲取組件的名稱（是否設置了組件名稱name，沒有則返回組件標簽名稱）
 const name: ?string = getComponentName(componentOptions)
 // 解構對象賦值常量
 const { include, exclude } = this
 if ( /* name不在inlcude中或者在exlude中則直接返回vnode */
  // not included
  (include && (!name || !matches(include, name))) ||
  // excluded
  (exclude && name && matches(exclude, name))
 ) {
  return vnode
 }
 const { cache, keys } = this
 const key: ?string = vnode.key == null
  // same constructor may get registered as different local components
  // so cid alone is not enough (#3269)
  ? componentOptions.Ctor.cid + (componentOptions.tag ? `::${componentOptions.tag}` : '')
  : vnode.key
 if (cache[key]) { // 判斷當前是否有緩存，有則取緩存的實例，無則進行緩存
  vnode.componentInstance = cache[key].componentInstance
  // make current key freshest
  remove(keys, key)
  keys.push(key)
 } else {
  cache[key] = vnode
  keys.push(key)
  // 判斷是否設置了最大緩存實例數量，超過則刪除最老的數據，
  if (this.max && keys.length > parseInt(this.max)) {
  pruneCacheEntry(cache, keys[0], keys, this._vnode)
  }
 }
 // 給vnode打上緩存標記
 vnode.data.keepAlive = true
 }
 return vnode || (slot && slot[0])
}
// 銷毀實例
function pruneCacheEntry (
 cache: VNodeCache,
 key: string,
 keys: Array<string>,
 current?: VNode
) {
 const cached = cache[key]
 if (cached && (!current || cached.tag !== current.tag)) {
 cached.componentInstance.$destroy()
 }
 cache[key] = null
 remove(keys, key)
}
// 緩存
function pruneCache (keepAliveInstance: any, filter: Function) {
 const { cache, keys, _vnode } = keepAliveInstance
 for (const key in cache) {
 const cachedNode: ?VNode = cache[key]
 if (cachedNode) {
  const name: ?string = getComponentName(cachedNode.componentOptions)
  // 組件name 不符合filler條件， 銷毀實例，移除cahe
  if (name && !filter(name)) {
  pruneCacheEntry(cache, key, keys, _vnode)
  }
 }
 }
}
// 篩選過濾函數
function matches (pattern: string | RegExp | Array<string>, name: string): boolean {
 if (Array.isArray(pattern)) {
 return pattern.indexOf(name) > -1
 } else if (typeof pattern === 'string') {
 return pattern.split(',').indexOf(name) > -1
 } else if (isRegExp(pattern)) {
 return pattern.test(name)
 }
 /* istanbul ignore next */
 return false
}
// 檢測 include 和 exclude 數據的變化，實時寫入讀取緩存或者刪除
mounted () {
 this.$watch('include', val => {
 pruneCache(this, name => matches(val, name))
 })
 this.$watch('exclude', val => {
 pruneCache(this, name => !matches(val, name))
 })
},

<!--exclude - 字符串或正則表達式。任何匹配的組件都不會被緩存。-->
<!--TODO 匹配首先檢查組件自身的 name 選項，如果 name 選項不可用，則匹配它的局部注冊名稱-->
<keep-alive :exclude="keepAliveConf.value">
 <router-view class="child-view" :key="$route.fullPath"></router-view>
</keep-alive>
<!-- 或者 -->
<keep-alive :include="keepAliveConf.value">
 <router-view class="child-view" :key="$route.fullPath"></router-view>
</keep-alive>
<!-- 具體使用 include 還是exclude 根據項目是否需要緩存的頁面數量多少來決定-->

// 路由組件命名集合
 var arr = ['component1', 'component2'];
 export default {value: routeList.join()};

import keepAliveConf from 'keepAliveConf.js'
Vue.mixin({
 methods: {
 // 傳入需要重置的組件名字
 resetKeepAive(name) {
  const conf = keepAliveConf.value;
  let arr = keepAliveConf.value.split(',');
  if (name && typeof name === 'string') {
   let i = arr.indexOf(name);
   if (i > -1) {
    arr.splice(i, 1);
    keepAliveConf.value = arr.join();
    setTimeout(() => {
     keepAliveConf.value = conf
    }, 500);
   }
  }
 },
 }
})