Astro middleware are functions that run on the server before a page is displayed to the user. Astro locals are a way to store data that is specific to the current request. We can use these features to store the user's account data, so that it is available to all pages.

Create a new file in the `src/` directory called `middleware.js`:

```js

```

To ensure the `locals` object is typed correctly, we can add a type definition for it in a `env.d.ts` file at the root of the project:

```ts

```

Now, use the `locals` object in the home page to redirect based on the user's login status. Overwrite the file in the `src/pages` directory called `index.astro`:

```js

```

If the user is logged in, they will be redirected to the account page. If they are not logged in, they will be redirected to the sign up page.