How to handle errors in Server Actions | Next.js Supabase SaaS Kit

Learn how to handle errors in Server Actions in the Next.js Supabase SaaS Kit

Generally speaking, you can handle Server Action in three ways:

You can use the try/catch block to catch errors and handle them in the catch block.
You can use a React ErrorBoundary component to catch errors
You can also use the special error.tsx file to handle errors at layout level.

Handling errors from a Server Action invoked by a Form

Let's assume we have a Form using a server action that throws an error:

async function serverActionWithError() {
  'use server';
  throw new Error(`This is error is in the Server Action`);
}
function FormWithServerAction() {
  return (
    <form action={serverActionWithError}>
      <button>Submit Form</button>
    </form>
  );
}
export default FormWithServerAction;

We can wrap our form using the ErrorBoundary component we have at ~/core/ui/ErrorBoundary, and handle the error from there:

import ErrorBoundary from '~/core/ui/ErrorBoundary';
import FormWithServerAction from './Form';
function FormWithErrorBoundary() {
  return (
    <ErrorBoundary fallback={<p>Something went wrong</p>}>
      <FormWithServerAction />
    </ErrorBoundary>
  );
}

If you click on the button, you'll see the error message rendered.

Handling errors from an imperatively invoked Server Action

If you are invoking a Server Action imperatively, we can wrap the useTransition hook in a try/catch block, and handle the error from there.

Let's assume we have a Server Action that throws an error:

'use server';
export async function serverActionWithError() {
  throw new Error(`This is error is in the Server Action`);
}

We can invoke it imperatively from a client component, and handle the error from there:

'use client';
import { useTransition } from 'react';
import { serverActionWithError } from './actions';
function ImperativeServerAction() {
  const [pending, startTransition] = useTransition();
  return (
    <button
      disabled={pending}
      onClick={() => {
        startTransition(async () => {
          try {
            await serverActionWithError()
          } catch (e) {
            alert('error');
          }
        });
      }}
    >
      Click Button
    </button>
  );
}
export default ImperativeServerAction;

If you click on the button, you'll see the alert popup with the error message.