钢结构网站建设建立了网站后如何发贴
目录
文章目录
概要
效果
完整代码
概要
摆了半年摊，好久没写代码了，今天有人问我怎么实现React-Router-dom类似标签页缓存。后面看了一下router的官网。很久以前用的是react-router v5那个比较容易实现。v6变化挺大，但了解react的机制和react-router的机制就容易了.
想做到切换标签保留页面的内容不变，就要了解react的机制
首先虚拟DOM的机制就是对比，如果找不到就会重新挂载，找到了就更新。
React-Router的机制就是匹配路径，找到了就返回对应的路由组件，找不到返回为null
思路就是v6版本提供了Outlet这个输出子路元素的组件
一般我们会这样写：
但如果要实现标签的话，就不能这样写。但是切换路由，地址一变它就替换了原来的了。所以要做的就是保留所有打开的标签的子路由元素：
主要目的就是保留所有的元素，隐藏路由就行，这样react diff时，还是会找到对应key的路由，这样它只是会更新路由的组件，而不会重新挂载。
如这样写：
效果
完整代码
新建一个html复制进去就可以运行了
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>React-router-dom tabs</title><script src="https://cdn.jsdelivr.net/npm/react@18.2.0/umd/react.production.min.js"></script><script src="https://cdn.jsdelivr.net/npm/react-dom@18.2.0/umd/react-dom.production.min.js"></script><script src="https://cdn.jsdelivr.net/npm/@babel/standalone@7.23.2/babel.min.js"></script><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/antd@5.10.1/dist/reset.min.css"><script src="https://cdn.jsdelivr.net/npm/dayjs@1.11.10/dayjs.min.js"></script><script src="https://cdn.jsdelivr.net/npm/antd@5.10.1/dist/antd.min.js"></script><script src="https://cdn.jsdelivr.net/npm/@ant-design/pro-components@2.6.30/dist/pro-components.min.js"></script><script src="https://cdn.jsdelivr.net/npm/@remix-run/router@1.10.0/dist/router.umd.min.js"></script><script src="https://cdn.jsdelivr.net/npm/react-router@6.17.0/dist/umd/react-router.production.min.js"></script><scriptsrc="https://cdn.jsdelivr.net/npm/react-router-dom@6.17.0/dist/umd/react-router-dom.production.min.js"></script>
</head>
<body><div id="app"></div><script type="text/babel" data-preset="env,react">const { useCallback, useMemo, useEffect, useRef, useState } = Reactconst { ProLayout } = ProComponentsconst { createHashRouter, useOutlet, Navigate, RouterProvider, useLocation, Link, useNavigate } = ReactRouterDOMconst { Tabs, Button, Space, Row, Col, Input, } = antdconst Home = () => {return <div>Home <Input></Input></div>}const DemoA = () => {return <div>DemoA <Input></Input></div>}const DemoB = () => {return <div>DemoB <Input></Input></div>}const ViewPage = (props) => {const outlet = useOutlet()return props.render(outlet)}const BasicLayout = () => {const nav = useNavigate()const location = useLocation()const route = routes[0]const [menuDataMap] = useState(() => new Map())const cacheOutletElements = useRef({}).currentconst [tabActiveKey, setTabActiveKey] = useState('')const [tabItems, setTabItems] = React.useState([])const addTab = useCallback((item) => {const existItem = tabItems.find(it => it.key === item.key)if (!existItem) {setTabItems([...tabItems, {key: item.key,path: item.path,label: item.name}])}setTabActiveKey(item.key)}, [tabItems])const handleSelectMenu = useCallback((selectedKeys) => {console.log('handleSelectMenu', selectedKeys)let menuKey = selectedKeys[selectedKeys.length - 1]let item = menuDataMap.get(menuKey)if (item && item.path) {addTab(item)}}, [addTab])const handleTabChange = useCallback((activeKey) => {setTabActiveKey(activeKey)const item = tabItems.find(d => d.key === activeKey)nav(item.path)}, [tabItems, nav])const handleTabEditChange = useCallback((activeKey, action) => {if (action === 'remove') {delete cacheOutletElements[activeKey]const newItems = tabItems.filter(d => d.key !== activeKey)setTabItems(newItems)if (newItems.length) {handleTabChange(newItems[0].key)}}}, [tabItems, handleTabChange])const renderView = useCallback((routeElement) => {if (!cacheOutletElements[tabActiveKey]) {cacheOutletElements[tabActiveKey] = <div>{routeElement}</div>}return Object.keys(cacheOutletElements).map(key => {const element = cacheOutletElements[key]if (key === tabActiveKey) {return React.cloneElement(element, {key: key,style: {display: 'block'}})} else {return React.cloneElement(element, {key: key,style: {display: 'none'}})}})}, [cacheOutletElements, tabActiveKey])return <ProLayout route={route} onSelect={handleSelectMenu} location={location} menuItemRender={(item, defaultDom, menuProps) => {if (item.children) {return defaultDom}menuDataMap.set(item.path, item)return <Link to={item.path}>{defaultDom}</Link>}}><Tabs hideAdd type='editable-card' onEdit={handleTabEditChange} activeKey={tabActiveKey} onChange={handleTabChange} items={tabItems}></Tabs><ViewPage render={renderView}></ViewPage></ProLayout>}const routes = [{path: '/',element: <BasicLayout></BasicLayout>,children: [{index: true,element: <Navigate to="/home"></Navigate>}, {path: 'home',name: "Home",element: <Home></Home>}, {path: 'a',name: "DemoA",element: <DemoA></DemoA>}, {path: 'b',name: "DemoB",element: <DemoB></DemoB>}]}]const router = createHashRouter(routes, {})const App = () => {return <RouterProvider router={router}></RouterProvider>}ReactDOM.createRoot(document.getElementById('app')).render(<App></App>)</script>
</body>
</html>