SvelteKit Fallback Errors

SvelteKit provides a robust mechanism for managing errors in your application. This guide details the process of implementing fallback error pages, which enhance user experience when unexpected issues occur.

Key Concepts

• Error Handling: SvelteKit enables you to catch errors and display user-friendly messages instead of generic error pages.
• Fallback Pages: These custom pages guide users during errors, ensuring they aren’t left confused.

Implementing Fallback Errors

Step 1: Create a Fallback Error Component

• To create a fallback error page, add a new component in your src/routes directory.
• For example, create a file named error.svelte:

<script>
  export let error; // This will hold error information
</script>

<h1>Something went wrong!</h1>
<p>{error.message}</p> 

Step 2: Update Your Routes

• In your route files, define how to manage errors.
• Use the load function in your route to catch errors:

// src/routes/+page.js
export async function load({ fetch }) {
  try {
    const res = await fetch('/api/data');
    if (!res.ok) {
      throw new Error('Failed to fetch data');
    }
    const data = await res.json();
    return { props: { data } };
  } catch (error) {
    return { error }; // Pass the error to the fallback component
  }
}

Step 3: Global Error Handling

• Set up a global error handler by creating a +error.svelte file in src/routes.
• This captures errors from any route in your application:

<script>
  export let error; // Capture error details
</script>

<h1>Error Occurred</h1>
<p>{error.message}</p>

Benefits of Fallback Errors

• User Experience: Users receive clear messages about what went wrong instead of confusing error pages.
• Debugging: Developers gain access to detailed error messages that assist in issue diagnosis.
• Consistency: Dedicated error pages ensure a consistent look and feel across your application.

Conclusion

Implementing fallback error handling in SvelteKit is straightforward and significantly improves user interaction during unexpected issues. By following the outlined steps, you can create a more robust and user-friendly application.