vue3 keepalive线上问题怎么解决

import { defineStore } from "pinia"; export const useKeepAliverStore = defineStore("useKeepAliverStore", { state: () => ({ caches: [] as any, scrollList: new Map(), // 缓存页面组件如果又滚动条的高度 }), actions: { add(name: string) { this.caches.push(name); }, remove(name: string) { console.log(this.caches, 'this.caches') this.caches = this.caches.filter((item: any) => item !== name); console.log(this.caches, 'this.caches') }, clear() { this.caches = [] } } });

import { useRoute, useRouter, onBeforeRouteLeave } from "vue-router"; import { useKeepAliverStore } from "@/store"; const useStore = useKeepAliverStore() export default { name:"record-month", beforeRouteEnter(to, from, next) { next(vm => { if(from.name === 'Home' && to.name === 'record-month') { useStore.add(to.name) } }); } } 

onBeforeRouteLeave((to, from) => { console.log(to.name, "onBeforeRouteLeave"); if (to.name === "new-detection-detail") { console.log(to, from, "进入详情页面不做处理"); } else { useStore.remove(from.name) console.log(to, from, "删除组件缓存"); } });

onActivated(() => { if(useStore.scrollList.get(routeName)) { const top = useStore.scrollList.get(routeName) refList.value.setScrollTop(Number(top)) } }); onDeactivated(() => { const top = refList.value.getScrollTop() useStore.scrollList.set(routeName, top) });

const setScrollTop = (value: any) => { const dom = document.querySelector('.van-pull-refresh') dom!.scrollTop = value }

onMounted(() => { scrollDom.value = document.querySelector('.van-pull-refresh') as HTMLElement const throttledFun = useThrottleFn(() => { console.log(scrollDom.value?.scrollTop, 'addEventListener') state.scrollTop = scrollDom.value!.scrollTop }, 500) if(scrollDom.value) { scrollDom.value.addEventListener('scroll',throttledFun) } }) const getScrollTop = () => { console.log('scrollDom.vaue', scrollDom.value?.scrollTop) return state.scrollTop }

https://vueuse.org/shared/usethrottlefn/#usethrottlefn

const instance = getCurrentInstance() console.log(instance.vnode.parent) // 这里便是keepalive组件vnode // 如果是在开发环境中可以查看到cache对象 instance.vnode.parent.__v_cache // vue源码中，在dev环境对cache进行暴露，生产环境是看不到的 if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) { ;(instance as any).__v_cache = cache }

git clone git@github.com:vuejs/core.git

pnpm i

npm i pnpm -g

// 在dev命令后添加 --source-map是从已转换的代码，映射到原始的源文件 "dev": "node scripts/dev.js --sourcemap"

pnpm run dev //则会出现以下，代表成功了（2022年5月27日），后期vue源代码作者可能会更新，相应的提示可能发生变更，请注意一下 > @3.2.36 dev H:\github\sourceCode\core > node scripts/dev.js --sourcemap watching: packages\vue\dist\vue.global.js //到..\..\core\packages\vue\dist便可以看到编译成功，以及可以查看到examples样例demo页面

     
 
Hello World
 
Hello World
 
Hello World
 组件一 组件二    
  

// 在setup初始化中，先获取keepalive实例 // getCurrentInstance() 可以获取当前组件的实例 const instance = getCurrentInstance()! // KeepAlive communicates with the instantiated renderer via the // ctx where the renderer passes in its internals, // and the KeepAlive instance exposes activate/deactivate implementations. // The whole point of this is to avoid importing KeepAlive directly in the // renderer to facilitate tree-shaking. const sharedContext = instance.ctx as KeepAliveContext // if the internal renderer is not registered, it indicates that this is server-side rendering, // for KeepAlive, we just need to render its children /// SSR 判断，暂时可以忽略掉即可。 if (__SSR__ && !sharedContext.renderer) { return () => { const children = slots.default && slots.default() return children && children.length === 1 ? children[0] : children } } // 通过Map存储缓存vnode, // 通过Set存储缓存的key(在外面设置的key，或者vnode的type) const cache: Cache = new Map() const keys: Keys = new Set() let current: VNode | null = null if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) { ;(instance as any).__v_cache = cache } const parentSuspense = instance.suspense const { renderer: { p: patch, m: move, um: _unmount, o: { createElement } } } = sharedContext // 创建了隐藏容器 const storageContainer = createElement('div') // 在实例上注册两个钩子函数 activate， deactivate sharedContext.activate = (vnode, container, anchor, isSVG, optimized) => { const instance = vnode.component! move(vnode, container, anchor, MoveType.ENTER, parentSuspense) // in case props have changed patch( instance.vnode, vnode, container, anchor, instance, parentSuspense, isSVG, vnode.slotScopeIds, optimized ) queuePostRenderEffect(() => { instance.isDeactivated = false if (instance.a) { invokeArrayFns(instance.a) } const vnodeHook = vnode.props && vnode.props.onVnodeMounted if (vnodeHook) { invokeVNodeHook(vnodeHook, instance.parent, vnode) } }, parentSuspense) if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) { // Update components tree devtoolsComponentAdded(instance) } } sharedContext.deactivate = (vnode: VNode) => { const instance = vnode.component! move(vnode, storageContainer, null, MoveType.LEAVE, parentSuspense) queuePostRenderEffect(() => { if (instance.da) { invokeArrayFns(instance.da) } const vnodeHook = vnode.props && vnode.props.onVnodeUnmounted if (vnodeHook) { invokeVNodeHook(vnodeHook, instance.parent, vnode) } instance.isDeactivated = true }, parentSuspense) if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) { // Update components tree devtoolsComponentAdded(instance) } } // 组件卸载 function unmount(vnode: VNode) { // reset the shapeFlag so it can be properly unmounted resetShapeFlag(vnode) _unmount(vnode, instance, parentSuspense, true) } // 定义 include和exclude变化时，对缓存进行动态处理 function pruneCache(filter?: (name: string) => boolean) { cache.forEach((vnode, key) => { const name = getComponentName(vnode.type as ConcreteComponent) if (name && (!filter || !filter(name))) { pruneCacheEntry(key) } }) } function pruneCacheEntry(key: CacheKey) { const cached = cache.get(key) as VNode if (!current || cached.type !== current.type) { unmount(cached) } else if (current) { // current active instance should no longer be kept-alive. // we can't unmount it now but it might be later, so reset its flag now. resetShapeFlag(current) } cache.delete(key) keys.delete(key) } // 可以发现通过include 可以配置被显示的组件， // 当然也可以设置exclude来配置不被显示的组件, // 组件切换时随时控制缓存 watch( () => [props.include, props.exclude], ([include, exclude]) => { include && pruneCache(name => matches(include, name)) exclude && pruneCache(name => !matches(exclude, name)) }, // prune post-render after `current` has been updated { flush: 'post', deep: true } ) // 定义当前组件Key // cache sub tree after render let pendingCacheKey: CacheKey | null = null // 这是一个重要的方法，设置缓存 const cacheSubtree = () => { // fix #1621, the pendingCacheKey could be 0 if (pendingCacheKey != null) { cache.set(pendingCacheKey, getInnerChild(instance.subTree)) } } onMounted(cacheSubtree) onUpdated(cacheSubtree) // 组件卸载的时候，对缓存列表进行循环判断处理 onBeforeUnmount(() => { cache.forEach(cached => { const { subTree, suspense } = instance const vnode = getInnerChild(subTree) if (cached.type === vnode.type) { // current instance will be unmounted as part of keep-alive's unmount resetShapeFlag(vnode) // but invoke its deactivated hook here const da = vnode.component!.da da && queuePostRenderEffect(da, suspense) return } unmount(cached) }) }) // 同时在keepAlive组件setup生命周期中，return () => {} 渲染的时候，对组件进行判断逻辑处理，同样对include和exclude判断渲染。 // 判断keepalive组件中的子组件，如果大于1个的话，直接警告处理了 // 另外如果渲染的不是虚拟dom（vNode）,则直接返回渲染即可。 return () => { // eslint-disable-next-line no-debugger console.log(props.include, 'watch-include') pendingCacheKey = null if (!slots.default) { return null } const children = slots.default() const rawVNode = children[0] if (children.length > 1) { if (__DEV__) { warn(`KeepAlive should contain exactly one component child.`) } current = null return children } else if ( !isVNode(rawVNode) || (!(rawVNode.shapeFlag & ShapeFlags.STATEFUL_COMPONENT) && !(rawVNode.shapeFlag & ShapeFlags.SUSPENSE)) ) { current = null return rawVNode } // 接下来处理时Vnode虚拟dom的情况，先获取vnode let vnode = getInnerChild(rawVNode) // 节点类型 const comp = vnode.type as ConcreteComponent // for async components, name check should be based in its loaded // inner component if available // 获取组件名称 const name = getComponentName( isAsyncWrapper(vnode) ? (vnode.type as ComponentOptions).__asyncResolved || {} : comp ) //这个算是最熟悉的通过props传递进行的参数，进行解构 const { include, exclude, max } = props // include判断 组件名称如果没有设置， 或者组件名称不在include中， // exclude判断 组件名称有了，或者匹配了 // 对以上两种情况都不进行缓存处理，直接返回当前vnode虚拟dom即可。 if ( (include && (!name || !matches(include, name))) || (exclude && name && matches(exclude, name)) ) { current = vnode return rawVNode } // 接下来开始处理有缓存或者要缓存的了 // 先获取一下vnode的key设置，然后看看cache缓存中是否存在 const key = vnode.key == null ? comp : vnode.key const cachedVNode = cache.get(key) // 这一段可以忽略了，好像时ssContent相关，暂时不管了，没看明白？？ // clone vnode if it's reused because we are going to mutate it if (vnode.el) { vnode = cloneVNode(vnode) if (rawVNode.shapeFlag & ShapeFlags.SUSPENSE) { rawVNode.ssContent = vnode } } // 上面判断了，如果没有设置key，则使用vNode的type作为key值 pendingCacheKey = key //判断上面缓存中是否存在vNode // if 存在的话，就将缓存中的vnode复制给当前的vnode // 同时还判断了组件是否为过渡组件 transition，如果是的话 需要注册过渡组件的钩子 // 同时先删除key，然后再重新添加key // else 不存在的话，就添加到缓存即可 // 并且要判断一下max最大缓存的数量是否超过了，超过了，则通过淘汰LPR算法，删除最旧的一个缓存 // 最后又判断了一下是否为Suspense。也是vue3新增的高阶组件。 if (cachedVNode) { // copy over mounted state vnode.el = cachedVNode.el vnode.component = cachedVNode.component if (vnode.transition) { // recursively update transition hooks on subTree setTransitionHooks(vnode, vnode.transition!) } // avoid vnode being mounted as fresh vnode.shapeFlag |= ShapeFlags.COMPONENT_KEPT_ALIVE // make this key the freshest keys.delete(key) keys.add(key) } else { keys.add(key) // prune oldest entry if (max && keys.size > parseInt(max as string, 10)) { pruneCacheEntry(keys.values().next().value) } } // avoid vnode being unmounted vnode.shapeFlag |= ShapeFlags.COMPONENT_SHOULD_KEEP_ALIVE current = vnode return isSuspense(rawVNode.type) ? rawVNode : vnode