md

src/utils/base/keepalive.js

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+/**
+ * base-keep-alive 主要解决问题场景：多级路由缓存;缓存同一个组件不同的页面,如何移除某个页面时不影响其他同组件的页面
+ * 前提：保证动态路由生成的route name 值都声明了且唯一
+ * 基于以上对keep-alive进行以下改造:
+ *   1. 组件名称获取更改为路由名称
+ *   2. cache缓存key也更改为路由名称
+ *   3. pruneCache
+ */
+const _toString = Object.prototype.toString
+function isRegExp(v) {
+  return _toString.call(v) === '[object RegExp]'
+}
+export function remove(arr, item) {
+  if (arr.length) {
+    const index = arr.indexOf(item)
+    if (index > -1) {
+      return arr.splice(index, 1)
+    }
+  }
+}
+/**
+ * 1. 主要更改了 name 值获取的规则
+ * @param {*} opts
+ */
+function getComponentName(opts) {
+  // return opts && (opts.Ctor.options.name || opts.tag)
+  return this.$route.path
+}
+function isDef(v) {
+  return v !== undefined && v !== null
+}
+function isAsyncPlaceholder(node) {
+  return node.isComment && node.asyncFactory
+}
+function getFirstComponentChild(children) {
+  if (Array.isArray(children)) {
+    for (let i = 0; i < children.length; i++) {
+      const c = children[i]
+      if (isDef(c) && (isDef(c.componentOptions) || isAsyncPlaceholder(c))) {
+        return c
+      }
+    }
+  }
+}
+function matches(pattern, name) {
+  if (Array.isArray(pattern)) {
+    return pattern.indexOf(name) > -1
+  } else if (typeof pattern === 'string') {
+    return pattern.split(',').indexOf(name) > -1
+  } else if (isRegExp(pattern)) {
+    return pattern.test(name)
+  }
+  /* istanbul ignore next */
+  return false
+}
+
+function pruneCache(keepAliveInstance, filter) {
+  console.log("🚀 ~ file: keepalive.js:58 ~ pruneCache ~ keepAliveInstance, filter:", keepAliveInstance, filter)
+  const { cache, keys, _vnode } = keepAliveInstance
+  for (const key in cache) {
+    const cachedNode = cache[key]
+    if (cachedNode) {
+      // ------------ 3. 之前默认从router-view取储存key值, 现在改为路由name, 所以这里得改成当前key
+      // const name = getComponentName.call(keepAliveInstance, cachedNode.componentOptions)
+      const name = key
+      if (name && !filter(name)) {
+        pruneCacheEntry(cache, key, keys, _vnode)
+      }
+    }
+  }
+}
+
+function pruneCacheEntry(
+  cache,
+  key,
+  keys,
+  current
+) {
+  const cached = cache[key]
+  if (cached && (!current || cached.tag !== current.tag)) {
+    cached.componentInstance.$destroy()
+  }
+  cache[key] = null
+  remove(keys, key)
+}
+
+const patternTypes = [String, RegExp, Array]
+
+export default {
+  name: 'keep-alive-custom', // 名称最好改一下，不要与原keep-alive一致
+  // abstract: true,
+  props: {
+    include: patternTypes,
+    exclude: patternTypes,
+    max: [String, Number]
+  },
+
+  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.$slots.default
+    const vnode = getFirstComponentChild(slot)
+    const componentOptions = vnode && vnode.componentOptions
+    if (componentOptions) {
+      // check pattern
+      const name = getComponentName.call(this, componentOptions)
+      // console.log("🚀 ~ file: keepalive.js:124 ~ render ~ name:", name)
+      // ---------- 对于没有name值得设置为路由得name, 支持vue-devtool组件名称显示
+      if (!componentOptions.Ctor.options.name) {
+        vnode.componentOptions.Ctor.options.name
+      }
+      const { include, exclude } = this
+      if (
+        // not included
+        (include && (!name || !matches(include, name))) ||
+        // excluded
+        (exclude && name && matches(exclude, name))
+      ) {
+        return vnode
+      }
+
+      const { cache, keys } = this
+      // ------------------- 储存的key值, 默认从router-view设置的key中获取
+      // const key = vnode.key == null
+      //   ? componentOptions.Ctor.cid + (componentOptions.tag ? `::${componentOptions.tag}` : '')
+      //   : vnode.key
+
+      // ------------------- 2. 储存的key值设置为路由中得name值
+      const key = name
+
+      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])
+  }
+}