Expected `server` export in actions file to be an object. Received undefined

Understanding the “Server Export in Actions File is Undefined” Error in AstroJS

When working with AstroJS server-side actions, you might encounter this error:

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Expected `server` export in actions file to be an object. Received undefined

This error occurs when Astro tries to use a server action but can’t find the expected server export object in your actions file.

Common Causes of the Server Actions Undefined Error

This error typically occurs when you try to import client-side code into a server actions file. The most common scenario is importing code that uses browser-specific types or APIs (like HTMLElement, window, or document) in a file that needs to run on the server.

Example of Problematic Code That Causes This Error

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import { validateForm } from './clientUtils'; // This file uses HTMLElement
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export const server = {
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  submitForm: async (data) => {
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    // This will fail because validateForm uses browser-only types
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    const isValid = validateForm(data);
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    // ...
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  },
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};

How to Fix the Server Actions Undefined Error

1. Separate your client and server code
2. Keep browser-specific code in client-side files only
3. Implement server-side validation separately

Here’s the corrected approach:

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export const server = {
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  submitForm: async (data) => {
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    // Implement server-side validation here
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    const isValid = validateServerSide(data);
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    // ...
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  },
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};
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function validateServerSide(data) {
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  // Server-safe validation logic
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  return true;
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}

Preventing Server Actions Undefined Errors with Code Protection

The best way to prevent this error is to create a protection.ts file that throws an error if the file is imported by a file that is not server side. Import this file in all your server only files.

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if (typeof window !== 'undefined') {
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  throw new Error('This file is not allowed to be imported by a client-side file');
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}

Best Practices for Working with Astro Server Actions

• Always check if your imported utilities use browser-specific APIs

• Keep client-side validation separate from server-side validation

• Use TypeScript to catch these issues early in development