beforeRouteLeave (to, from, next) {

    if (to.name === 'pageA') {   /* pageA是需要跳转的路由   */

      // console.log('返回管理页面')

      if (this.$vnode && this.$vnode.data.keepAlive) {

        if (this.$vnode.parent && this.$vnode.parent.componentInstance && this.$vnode.parent.componentInstance.cache) {

          if (this.$vnode.componentOptions) {

            var key = this.$vnode.key == null

              ? this.$vnode.componentOptions.Ctor.cid + (this.$vnode.componentOptions.tag ? `::${this.$vnode.componentOptions.tag}` : '')

              : this.$vnode.key

            var cache = this.$vnode.parent.componentInstance.cache

            var keys = this.$vnode.parent.componentInstance.keys

            if (cache[key]) {

              if (keys.length) {

                var index = keys.indexOf(key)

                if (index > -1) {

                  keys.splice(index, 1)

                }

              }

              delete cache[key]

            }

          }

        }

      }

      this.$destroy()

    }

    next()

  },