react-router-dom 库作用
`react-router-dom`是一个用于在 React 应用中实现路由功能的重要库
一、实现页面导航
1. 声明式路由定义
1.1 基本原理
使用`react-router-dom`可以在代码中直接定义一个路由规则，如从`/home`路径导航到`Home`组件。
1.2 代码示例
`Router` 路由根容器，`Routes` 包裹所有的路由规则，`Route` 定义了一条具体的路由，包括路径（`path`）和对应的组件（`element`）。
import { BrowserRouter as Router, Route, Routes } from "react-router-dom";
import Home from "./Home";
import About from "./About";
const App = () => {
return (
<Router>
<Routes>
<Route path="/home" element={<Home />} />
<Route path="/about" element={<About />} />
</Routes>
</Router>
);
};
export default App;2. 动态路由匹配
2.1 处理可变路径参数
可以定义一个路由路径为`/user/:id`，其中`:id`就是动态参数。
2.2 代码示例
import {
BrowserRouter as Router,
Route,
Routes,
useParams,
} from "react-router-dom";
const UserDetail = () => {
const { id } = useParams();
return (
<div>
<h1>User Detail for ID: {id}</h1>
</div>
);
};
const App = () => {
return (
<Router>
<Routes>
<Route path="/user/:id" element={<UserDetail />} />
</Routes>
</Router>
);
};
export default App;二、嵌套路由和布局管理
1. 嵌套路由实现
1.1 构建多层级页面结构
例如：有一个父路由`/blog`，其下包含子路由`/blog/posts`（文章列表）和`/blog/post/:id`（单个文章详情）。
1.2 代码示例
import { BrowserRouter as Router, Route, Routes } from "react-router-dom";
import Blog from "./Blog";
import BlogPosts from "./BlogPosts";
import BlogPostDetail from "./BlogPostDetail";
const App = () => {
return (
<Router>
<Routes>
<Route path="/blog" element={<Blog />}>
<Route path="posts" element={<BlogPosts />} />
<Route path="post/:id" element={<BlogPostDetail />} />
</Route>
</Routes>
</Router>
);
};
export default App;2. 布局管理与共享布局组件
2.1 统一布局应用
假设我们有一个名为`Layout`的布局组件，包含了导航栏和侧边栏。
2.2 代码示例
import { BrowserRouter as Router, Route, Routes } from "react-router-dom";
import Layout from "./Layout";
import Home from "./Home";
import About from "./About";
const App = () => {
return (
<Router>
<Routes>
<Route path="/" element={<Layout />}>
<Route path="home" element={<Home />} />
<Route path="about" element={<About />} />
</Route>
</Routes>
</Router>
);
};
export default App;三、代码分割和懒加载
1. 懒加载原理和优势
1.1 优化初始加载性能
例如：将每个模块的组件懒加载，使得应用在初始启动时只加载必要的组件。
1.2 代码示例
import {
BrowserRouter as Router,
Route,
Routes,
lazy,
Suspense,
} from "react-router-dom";
const Dashboard = lazy(() => import("./Dashboard"));
const Reports = lazy(() => import("./Reports"));
const Settings = lazy(() => import("./Settings"));
const App = () => {
return (
<Router>
<Routes>
<Route
path="/dashboard"
element={
<Suspense fallback={<div>Loading...</div>}>
<Dashboard />
</Suspense>
}
/>
<Route
path="/reports"
element={
<Suspense fallback={<div>Loading...</div>}>
<Reports />
</Suspense>
}
/>
<Route
path="/settings"
element={
<Suspense fallback={<div>Loading...</div>}>
<Settings />
</Suspense>
}
/>
</Routes>
</Router>
);
};
export default App;