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路由器上下文

TanStack Router 的路由器上下文是一个非常强大的工具,可用于依赖注入等多种用途。顾名思义,路由器上下文通过路由器传递,并向下传递到每个匹配的路由。在层次结构中的每个路由,上下文都可以被修改或添加。以下是一些实际使用路由器上下文的方式:

  • 依赖注入
    • 您可以提供依赖项(例如加载器函数、数据获取客户端、变更服务),路由及其所有子路由可以访问和使用这些依赖项,而无需直接导入或创建。
  • 面包屑导航
    • 虽然每个路由的主上下文对象在下降时会合并,但每个路由的唯一上下文也会被存储,使得可以将面包屑或方法附加到每个路由的上下文中。
  • 动态元标签管理
    • 您可以将元标签附加到每个路由的上下文中,然后使用元标签管理器在用户浏览网站时动态更新页面上的元标签。

这些只是路由器上下文的建议用途。您可以根据自己的需求使用它!

类型化路由器上下文

与其他所有内容一样,根路由器上下文是严格类型化的。这种类型可以通过任何路由的 beforeLoad 选项进行扩展,因为它会在路由匹配树中向下合并。要约束根路由器上下文的类型,您必须使用 createRootRouteWithContext<YourContextTypeHere>()(routeOptions) 函数创建新的路由器上下文,而不是使用 createRootRoute() 函数创建根路由。以下是一个示例:

tsx
import {
  createRootRouteWithContext,
  createRouter,
} from '@tanstack/react-router'

interface MyRouterContext {
  user: User
}

// Use the routerContext to create your root route
const rootRoute = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})

const routeTree = rootRoute.addChildren([
  // ...
])

// Use the routerContext to create your router
const router = createRouter({
  routeTree,
})
import {
  createRootRouteWithContext,
  createRouter,
} from '@tanstack/react-router'

interface MyRouterContext {
  user: User
}

// Use the routerContext to create your root route
const rootRoute = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})

const routeTree = rootRoute.addChildren([
  // ...
])

// Use the routerContext to create your router
const router = createRouter({
  routeTree,
})

传递初始路由器上下文

路由器上下文在实例化时传递给路由器。您可以通过 context 选项将初始路由器上下文传递给路由器:

Tip

如果您的上下文有任何必需的属性,如果您没有在初始路���器上下文中传递它们,您将看到 TypeScript 错误。如果您的所有上下文属性都是可选的,您将不会看到 TypeScript 错误,传递上下文将是可选的。如果您不传递路由器上下文,它默认为 {}

tsx
import { createRouter } from '@tanstack/react-router'

// Use the routerContext you created to create your router
const router = createRouter({
  routeTree,
  context: {
    user: {
      id: '123',
      name: 'John Doe',
    },
  },
})
import { createRouter } from '@tanstack/react-router'

// Use the routerContext you created to create your router
const router = createRouter({
  routeTree,
  context: {
    user: {
      id: '123',
      name: 'John Doe',
    },
  },
})

使路由器上下文失效

如果您需要使传递给路由器的上下文状态失效,您可以调用 invalidate 方法告诉路由器重新计算上下文。当您需要更新上下文状态并让路由器为所有路由重新计算上下文时,这很有用。

tsx
function useAuth() {
  const router = useRouter()
  const [user, setUser] = useState<User | null>(null)

  useEffect(() => {
    const unsubscribe = auth.onAuthStateChanged((user) => {
      setUser(user)
      router.invalidate()
    })

    return unsubscribe
  }, [])

  return user
}
function useAuth() {
  const router = useRouter()
  const [user, setUser] = useState<User | null>(null)

  useEffect(() => {
    const unsubscribe = auth.onAuthStateChanged((user) => {
      setUser(user)
      router.invalidate()
    })

    return unsubscribe
  }, [])

  return user
}

使用路由器上下文

一旦您定义了路由器上下文类型,您可以在路由定义中使用它:

tsx
// src/routes/todos.tsx
export const Route = createFileRoute('/todos')({
  component: Todos,
  loader: ({ context }) => fetchTodosByUserId(context.user.id),
})
// src/routes/todos.tsx
export const Route = createFileRoute('/todos')({
  component: Todos,
  loader: ({ context }) => fetchTodosByUserId(context.user.id),
})

您甚至可以注入数据获取和变更实现本身!事实上,这是强烈推荐的 😜

让我们尝试使用一个简单的函数来获取一些待办事项:

tsx
const fetchTodosByUserId = async ({ userId }) => {
  const response = await fetch(`/api/todos?userId=${userId}`)
  const data = await response.json()
  return data
}

const router = createRouter({
  routeTree: rootRoute,
  context: {
    userId: '123',
    fetchTodosByUserId,
  },
})
const fetchTodosByUserId = async ({ userId }) => {
  const response = await fetch(`/api/todos?userId=${userId}`)
  const data = await response.json()
  return data
}

const router = createRouter({
  routeTree: rootRoute,
  context: {
    userId: '123',
    fetchTodosByUserId,
  },
})

然后,在您的路由中:

tsx
// src/routes/todos.tsx
export const Route = createFileRoute('/todos')({
  component: Todos,
  loader: ({ context }) => context.fetchTodosByUserId(context.userId),
})
// src/routes/todos.tsx
export const Route = createFileRoute('/todos')({
  component: Todos,
  loader: ({ context }) => context.fetchTodosByUserId(context.userId),
})

如何使用外部数据获取库?

tsx
import {
  createRootRouteWithContext,
  createRouter,
} from '@tanstack/react-router'

interface MyRouterContext {
  queryClient: QueryClient
}

const rootRoute = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})

const queryClient = new QueryClient()

const router = createRouter({
  routeTree: rootRoute,
  context: {
    queryClient,
  },
})
import {
  createRootRouteWithContext,
  createRouter,
} from '@tanstack/react-router'

interface MyRouterContext {
  queryClient: QueryClient
}

const rootRoute = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})

const queryClient = new QueryClient()

const router = createRouter({
  routeTree: rootRoute,
  context: {
    queryClient,
  },
})

然后,在您的路由中:

tsx
// src/routes/todos.tsx
export const Route = createFileRoute('/todos')({
  component: Todos,
  loader: async ({ context }) => {
    await context.queryClient.ensureQueryData({
      queryKey: ['todos', { userId: user.id }],
      queryFn: fetchTodos,
    })
  },
})
// src/routes/todos.tsx
export const Route = createFileRoute('/todos')({
  component: Todos,
  loader: async ({ context }) => {
    await context.queryClient.ensureQueryData({
      queryKey: ['todos', { userId: user.id }],
      queryFn: fetchTodos,
    })
  },
})

如何使用 React Context/Hooks?

当尝试在路由的 beforeLoadloader 函数中使用 React Context 或 Hooks 时,重要的是要记住 React 的Hooks 规则。您不能在非 React 函数中使用钩子,因此不能在 beforeLoadloader 函数中使用钩子。

那么,我们如何在路由的 beforeLoadloader 函数中使用 React Context 或 Hooks 呢?我们可以使用路由器上下文将 React Context 或 Hooks 传递给路由的 beforeLoadloader 函数。

让我们看一个设置示例,其中我们将 useNetworkStrength 钩子传递给路由的 loader 函数:

  • src/routes/__root.tsx
tsx
// First, make sure the context for the root route is typed
import { createRootRouteWithContext } from '@tanstack/react-router'
import { useNetworkStrength } from '@/hooks/useNetworkStrength'

interface MyRouterContext {
  networkStrength: ReturnType<typeof useNetworkStrength>
}

export const Route = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})
// First, make sure the context for the root route is typed
import { createRootRouteWithContext } from '@tanstack/react-router'
import { useNetworkStrength } from '@/hooks/useNetworkStrength'

interface MyRouterContext {
  networkStrength: ReturnType<typeof useNetworkStrength>
}

export const Route = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})

在这个例子中,我们会在使用 <RouterProvider /> 渲染路由器之前实例化钩子。这样,钩子将在 React 环境中调用,因此遵守 Hooks 规则。

  • src/router.tsx
tsx
import { createRouter } from '@tanstack/react-router'

import { routeTree } from './routeTree.gen'

export const router = createRouter({
  routeTree,
  context: {
    networkStrength: undefined!, // We'll set this in React-land
  },
})
import { createRouter } from '@tanstack/react-router'

import { routeTree } from './routeTree.gen'

export const router = createRouter({
  routeTree,
  context: {
    networkStrength: undefined!, // We'll set this in React-land
  },
})
  • src/main.tsx
tsx
import { RouterProvider } from '@tanstack/react-router'
import { router } from './router'

import { useNetworkStrength } from '@/hooks/useNetworkStrength'

function App() {
  const networkStrength = useNetworkStrength()
  // Inject the returned value from the hook into the router context
  return <RouterProvider router={router} context={{ networkStrength }} />
}

// ...
import { RouterProvider } from '@tanstack/react-router'
import { router } from './router'

import { useNetworkStrength } from '@/hooks/useNetworkStrength'

function App() {
  const networkStrength = useNetworkStrength()
  // Inject the returned value from the hook into the router context
  return <RouterProvider router={router} context={{ networkStrength }} />
}

// ...

现在,在我们路由的 loader 函数中,我们可以从路由器上下文访问 networkStrength 钩子:

  • src/routes/posts.tsx
tsx
import { createFileRoute } from '@tanstack/react-router'

export const Route = createFileRoute('/posts')({
  component: Posts,
  loader: ({ context }) => {
    if (context.networkStrength === 'STRONG') {
      // Do something
    }
  },
})
import { createFileRoute } from '@tanstack/react-router'

export const Route = createFileRoute('/posts')({
  component: Posts,
  loader: ({ context }) => {
    if (context.networkStrength === 'STRONG') {
      // Do something
    }
  },
})

修改路由器上下文

路由器上下文沿着路由树向下传递,并在每个路由处合并。这意味着您可以在每个路由处修改上下文,修改后的内容将对所有子路由可用。以下是一个示例:

  • src/routes/__root.tsx
tsx
import { createRootRouteWithContext } from '@tanstack/react-router'

interface MyRouterContext {
  foo: boolean
}

export const Route = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})
import { createRootRouteWithContext } from '@tanstack/react-router'

interface MyRouterContext {
  foo: boolean
}

export const Route = createRootRouteWithContext<MyRouterContext>()({
  component: App,
})
  • src/router.tsx
tsx
import { createRouter } from '@tanstack/react-router'

import { routeTree } from './routeTree.gen'

const router = createRouter({
  routeTree,
  context: {
    foo: true,
  },
})
import { createRouter } from '@tanstack/react-router'

import { routeTree } from './routeTree.gen'

const router = createRouter({
  routeTree,
  context: {
    foo: true,
  },
})
  • src/routes/todos.tsx
tsx
import { createFileRoute } from '@tanstack/react-router'

export const Route = createFileRoute('/todos')({
  component: Todos,
  beforeLoad: () => {
    return {
      bar: true,
    }
  },
  loader: ({ context }) => {
    context.foo // true
    context.bar // true
  },
})
import { createFileRoute } from '@tanstack/react-router'

export const Route = createFileRoute('/todos')({
  component: Todos,
  beforeLoad: () => {
    return {
      bar: true,
    }
  },
  loader: ({ context }) => {
    context.foo // true
    context.bar // true
  },
})

处理累积的路由上下文

上下文,特别是隔离的路由 context 对象,使得累积和处理所有匹配路由的路由上下文对象变得非常简单。以下是一个示例,我们使用所有匹配的路由上下文来生成面包屑导航:

tsx
// src/routes/__root.tsx
export const Route = createRootRoute({
  component: () => {
    const matches = useRouterState({ select: (s) => s.matches })

    const breadcrumbs = matches
      .filter((match) => match.context.getTitle)
      .map(({ pathname, context }) => {
        return {
          title: context.getTitle(),
          path: pathname,
        }
      })

    // ...
  },
})
// src/routes/__root.tsx
export const Route = createRootRoute({
  component: () => {
    const matches = useRouterState({ select: (s) => s.matches })

    const breadcrumbs = matches
      .filter((match) => match.context.getTitle)
      .map(({ pathname, context }) => {
        return {
          title: context.getTitle(),
          path: pathname,
        }
      })

    // ...
  },
})

使用相同的路由上下文,我们还可以为页面的 <head> 生成标题标签:

tsx
// src/routes/__root.tsx
export const Route = createRootRoute({
  component: () => {
    const matches = useRouterState({ select: (s) => s.matches })

    const matchWithTitle = [...matches]
      .reverse()
      .find((d) => d.context.getTitle)

    const title = matchWithTitle?.context.getTitle() || 'My App'

    return (
      <html>
        <head>
          <title>{title}</title>
        </head>
        <body>{/* ... */}</body>
      </html>
    )
  },
})
// src/routes/__root.tsx
export const Route = createRootRoute({
  component: () => {
    const matches = useRouterState({ select: (s) => s.matches })

    const matchWithTitle = [...matches]
      .reverse()
      .find((d) => d.context.getTitle)

    const title = matchWithTitle?.context.getTitle() || 'My App'

    return (
      <html>
        <head>
          <title>{title}</title>
        </head>
        <body>{/* ... */}</body>
      </html>
    )
  },
})