目录
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
javascript
<!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>
<script
src="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 } = React
const { ProLayout } = ProComponents
const { createHashRouter, useOutlet, Navigate, RouterProvider, useLocation, Link, useNavigate } = ReactRouterDOM
const { Tabs, Button, Space, Row, Col, Input, } = antd
const 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({}).current
const [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>