useActionState is Not a Function? Here’s What You’re Doing Wrong

If you’ve tried using useActionState in your React project and hit the error:

“TypeError: useActionState is not a function”

You’re not alone. This confusing error has frustrated many developers—especially those working with modern frameworks like Next.js or experimenting with React 18’s latest features.

In this blog, we’ll dive deep into this error, why it happens, and how to fix it. We’ll also break down what useActionState is, when to use it, and the most common pitfalls that lead to this error.

What Is useActionState?

useActionState is a hook introduced in React 18.2. It allows you to handle form submissions and user actions declaratively. Instead of managing multiple pieces of state for things like success messages, errors, or form input validation, you can centralize it all using this single hook.

const [state, formAction] = useActionState(async (prev, formData) => {
  // Your logic here
  return newState;
}, initialState);

It returns:

• A state value that updates after every action
• An action function you assign to a form’s action attribute

This hook is particularly useful in frameworks like Next.js App Router, which supports React Server Components and Server Actions.

Understanding the Error: useActionState is not a function

Let’s get to the heart of the problem. This error occurs when you try to call useActionState, but React can’t find it—or doesn’t recognize it as a function.

Here’s what causes this:

1. You’re Using an Older Version of React

✅ The Fix: You must be using React 18.2 or later.

useActionState was added in React 18.2. If you’re using an earlier version (like 18.0.0 or 17.x), this hook simply doesn’t exist.

To check your version, run:

npm list react

Or in your package.json:

"react": "^18.2.0",
"react-dom": "^18.2.0"

If it’s anything below 18.2, update it:

npm install react@latest react-dom@latest

2. Incorrect React Import

Another common mistake is importing useActionState from the wrong place—or forgetting to import it altogether.

🛑 Wrong:

import { useActionState } from 'next/navigation'; // This will not work

✅ Correct:

import { useActionState } from 'react';

Make sure you’re importing it from React itself, not from next/*, react-dom, or other packages.

3. Using It in an Unsupported Environment

useActionState works only inside React Client Components. If you accidentally use it in a Server Component, you’ll hit this error or a similar one saying:

“Hooks can only be called inside of the body of a function component”

✅ The Fix:

• Ensure your component is marked with 'use client' at the top.

'use client';

import { useActionState } from 'react';

export default function MyForm() {
  const [state, action] = useActionState(...);
}

React Server Components (used in Next.js app/ directory) default to server context unless explicitly marked as client-side. useActionState is a hook, and like all React hooks, it can only be used in client components.

4. You’re Using an Unsupported Framework or Build Tool

Frameworks like Create React App (CRA) or older versions of Vite may not support the experimental features needed to use useActionState properly—especially with Server Actions or form actions.

✅ The Fix:

• Prefer using frameworks like Next.js App Router (React 18+ and server components ready)
• Use React with updated bundlers like Vite 5 or Webpack 5
• Ensure your build toolchain recognizes React 18.2 features

5. You’re Confusing useActionState with useFormState

Both useActionState and useFormState serve similar purposes—handling form state—but they are used differently and are often confused.

If you’re copying an example from a useFormState tutorial but trying to use useActionState, it may not work as expected.

Example: Correct Usage of useActionState

Here’s a working example of a contact form using useActionState.

'use client';

import { useActionState } from 'react';

export default function ContactForm() {
  const [formState, formAction] = useActionState(async (prevState, formData) => {
    const message = formData.get('message');

    if (!message) {
      return { error: 'Message is required', success: null };
    }

    await new Promise((res) => setTimeout(res, 1000)); // simulate async call
    return { success: 'Message sent successfully!', error: null };
  }, { success: null, error: null });

  return (
    <form action={formAction}>
      <textarea name="message" placeholder="Write your message" />
      <button type="submit">Send</button>
      {formState.error && <p style={{ color: 'red' }}>{formState.error}</p>}
      {formState.success && <p style={{ color: 'green' }}>{formState.success}</p>}
    </form>
  );
}

Key Things to Notice:

• 'use client'; at the top
• Hook imported from 'react'
• React version is 18.2+
• No external state hooks like useState or useEffect needed

Pro Tip: How to Polyfill or Fallback

If you’re using a React version below 18.2 and can’t upgrade, you’ll need to replicate useActionState with a custom hook using useReducer.

function useManualActionState(reducer, initialState) {
  const [state, dispatch] = React.useReducer(reducer, initialState);

  const action = async (formData) => {
    const nextState = await reducer(state, formData);
    dispatch({ type: 'update', payload: nextState });
  };

  return [state, action];
}

This won’t provide full useActionState integration with the <form> element, but it’s a stopgap until you upgrade React.

Common Fixes for useActionState is not a Function

Conclusion

The error useActionState is not a function usually stems from version mismatches, incorrect usage, or unsupported environments. The good news? It’s easy to fix once you know what to look for.

useActionState is a modern, powerful hook that simplifies form logic, especially when paired with server actions or API calls. If you’re building apps with React 18.2+ or using frameworks like Next.js, mastering this hook can make your forms cleaner, safer, and more reactive.

Now that you know the root causes and how to solve them, you can avoid hours of head-scratching and focus on what really matters—building great user experiences.