React-Router-Dom 6 - 如何动态渲染组件？

Question

My old method:

          <Route
            key={i}
            path={path}
            render={(props) => {
              if (!localStorage.getItem("token")) {
                <Redirect
                to={{ pathname: "/login", state: { from: props.location } }}
                />
              }
              return (
                <AuthLayout>
                  <Component {...props} />
                </AuthLayout>
              );
            }}
          />

Replacing render with the new element gives me:

Functions are not valid as a React child. This may happen if you return a Component instead of from render

Apparently the new API simply expects:

          <Route
            key={i}
            path={path}
            element={
                <Component />
            }
          />

What I'm really trying to accomplish is to dynamically render the component as such:

        {authProtectedRoutes.map(({ path, Component }, i) => {
          <Route
            key={i}
            path={path}
            element={
              // If no auth token, redirect to login
              if (!token) {
                <Navigate to="/login" />
              } else {
                <AuthLayout>
                  <Component />
                </AuthLayout>
              }
            }
          />
        })}

Not sure how to do this...

EDIT:

My array of components is as such:

const authProtectedRoutes = [
  { path: "/dashboard", Component: Dashboard },
  { path: "/pages-starter", Component: StarterPage },

When I try to return Component in my loop I get:

React.jsx: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.

Answer 1

element={
  // If no auth token, redirect to login
  if (!token) {
    <Navigate to="/login" />
  } else {
    <AuthLayout>
      <Component />
    </AuthLayout>
  }
}

You can't do an if in the middle of jsx, but you can do a conditional operator:

element={!token ? (
  <Navigate to="/login" />
) : (
  <AuthLayout>
    <Component />
  </AuthLayout>
)}

Answer 2

The element prop expects a ReactNode ( aka JSX ) and not javascript ( ie the if-statement ).

Since it seems you render your authenticated routes in bulk a more optimal solution would be to wrap them all in a single AuthLayout component that checks the token. Instead of rendering the children prop it renders an Outlet for nested routes to be rendered into.

Example:

const AuthLayout = ({ token }) => {
  // ... existing AuthLayout logic

  return token
    ? (
      <div /* awesome auth layout CSS style */>
        ...
        <Outlet /> // <-- nested routes render here
      </div>
    )
    : <Navigate to="/login" />;
};

Don't forget to return the Route from the map callback.

<Route element={<AuthLayout token={token} />}>
  {authProtectedRoutes.map(({ path, Component }) => (
    <Route key={path} path={path} element={<Component />} />
  ))}
</Route>

Answer 3

Nice routing-related question. First of all, I found useful code example from react-router-dom's github: https://github.com/remix-run/react-router/blob/2cd8266765925f8e4651d7caf42ebe60ec8e163a/examples/auth/src/App.tsx#L104

Here, instead of putting some logics inside "element" or "render" authors suggest to implement additional RequireAuth component and use it in routing setup like following:

<Route
  path="/protected"
  element={
    <RequireAuth>
      <SomePageComponent />
    </RequireAuth>
  }
....

This approach would allow to incapsulate auth-related checks inside this new RequireAuth component and as a result make your application routing setup more "lightweight"

As a "brief" example, I created following piece of code you could reference to:

function App() {
    return (
        <BrowserRouter>
            <AppRoutes />
        </BrowserRouter>
    );
}


const RequireAuth = ({ children }) => {
    const token = localStorage.getItem('token');
    const currentUrl = useHref();
    return !token ? (
        <Navigate to={`/login?redirect=${currentUrl}`} />
    ) : (
        children
    );
};

const authProtectedRoutes = [
    { path: '/', component: PaymentsPage },
    { path: '/user', component: UserInfoPage },
];

const AppRoutes = () => (
    <Routes>
        {authProtectedRoutes.map((r) => (
            <Route
                key={r.path}
                path={r.path}
                element={
                    <RequireAuth>
                        <AuthLayout>
                            <r.component />
                        </AuthLayout>
                    </RequireAuth>
                }
            />
        ))}
        <Route path="/login" element={<LoginPage />} />
        <Route path="*" element={<NotFoundPage />} />
    </Routes>
);