fix: the cache problem in tabs mode;🐛

修复：多页签模式下的缓存问题；

src/components/cache/AKeepAlive.js

@@ -0,0 +1,141 @@
+import {isDef, isRegExp, remove} from '@/utils/util'
+
+const patternTypes = [String, RegExp, Array]
+
+function matches (pattern, name) {
+  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 getComponentName (opts) {
+  return opts && (opts.Ctor.options.name || opts.tag)
+}
+
+function getFirstComponentChild (children) {
+  if (Array.isArray(children)) {
+    for (let i = 0; i < children.length; i++) {
+      const c = children[i]
+      if (isDef(c) && (isDef(c.componentOptions) || c.isAsyncPlaceholder)) {
+        return c
+      }
+    }
+  }
+}
+
+function pruneCache (keepAliveInstance, filter) {
+  const { cache, keys, _vnode } = keepAliveInstance
+  for (const key in cache) {
+    const cachedNode = cache[key]
+    if (cachedNode) {
+      const name = getComponentName(cachedNode.componentOptions)
+      if (name && !filter(name)) {
+        pruneCacheEntry(cache, key, keys, _vnode)
+      }
+    }
+  }
+}
+
+function pruneCacheEntry (cache, key, keys, current) {
+  const cached = cache[key]
+  if (cached && (!current || cached.tag !== current.tag)) {
+    cached.componentInstance.$destroy()
+  }
+  cache[key] = null
+  remove(keys, key)
+}
+
+export default {
+  name: 'AKeepAlive',
+  abstract: true,
+  model: {
+    prop: 'clearCaches',
+    event: 'clear',
+  },
+  props: {
+    include: patternTypes,
+    exclude: patternTypes,
+    max: [String, Number],
+    clearCaches: Array
+  },
+
+  watch: {
+    clearCaches: function(val) {
+      if (val && val.length > 0) {
+        const {cache, keys} = this
+        val.forEach(key => {
+          pruneCacheEntry(cache, key, keys, this._vnode)
+        })
+        this.$emit('clear', [])
+      }
+    }
+  },
+
+  created() {
+    this.cache = Object.create(null)
+    this.keys = []
+  },
+
+  destroyed () {
+    for (const key in this.cache) {
+      pruneCacheEntry(this.cache, key, this.keys)
+    }
+  },
+
+  mounted () {
+    this.$watch('include', val => {
+      pruneCache(this, name => matches(val, name))
+    })
+    this.$watch('exclude', val => {
+      pruneCache(this, name => !matches(val, name))
+    })
+  },
+
+  render () {
+    const slot = this.$slots.default
+    const vnode = getFirstComponentChild(slot)
+    const componentOptions = vnode && vnode.componentOptions
+    if (componentOptions) {
+      // check pattern
+      const name = getComponentName(componentOptions)
+      const { include, exclude } = this
+      if (
+        // not included
+        (include && (!name || !matches(include, name))) ||
+        // excluded
+        (exclude && name && matches(exclude, name))
+      ) {
+        return vnode
+      }
+
+      const { cache, keys } = this
+      const key = vnode.key == null
+        // same constructor may get registered as different local components
+        // so cid alone is not enough (#3269)
+        ? componentOptions.Ctor.cid + (componentOptions.tag ? `::${componentOptions.tag}` : '')
+        : vnode.key
+      if (cache[key]) {
+        vnode.componentInstance = cache[key].componentInstance
+        // make current key freshest
+        remove(keys, key)
+        keys.push(key)
+      } else {
+        cache[key] = vnode
+        keys.push(key)
+        // prune oldest entry
+        if (this.max && keys.length > parseInt(this.max)) {
+          pruneCacheEntry(cache, keys[0], keys, this._vnode)
+        }
+      }
+
+      vnode.data.keepAlive = true
+    }
+    return vnode || (slot && slot[0])
+  }
+}