createClient

The createClient function is the core utility in next-server-actions. It allows you to define shared logic—such as middleware, context, and error handling—that will automatically be applied to all your server actions.

This centralizes logic like authentication, context injection, and error reporting, helping you build cleaner and more maintainable apps.

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Usage

import { createClient } from "next-server-actions";

export const createServerAction = createClient({
  middleware: async () => {
    // Optional: auth, permissions, etc.
  },
  context: async () => {
    // Optional: shared user/session info
  },
  onError: async (error) => {
    // Optional: global error logging
  },
});

You can then use this createServerAction function to define individual server actions.

info

Want to know more about how to define server actions? See createServerAction.

Options

middleware

middleware?: () => Promise<{ message: string; }> | void

Runs before your server action logic. If it returns an object with a message, the action will be short-circuited and that message will be returned.

Useful for things like:

• Authentication
• Permission checks

Example

export const createServerAction = createClient({
  middleware: async () => {
    const user = await getUser();

    if (!user) {
      return { message: "unauthorized" };
    }
  }
});

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context

context?: () => Promise<C>

Injects shared data into all server actions. The returned object is passed as the second argument to your action handler.

Perfect for:

• Current user
• Feature flags
• Environment config

Example

export const createServerAction = createClient({
  context: async () => {
    const user = await getUser();

    return { user };
  }
});

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onError

onError?: (error: unknown) => Promise<void>

A global error handler. It’s called whenever a server action throws.

Use cases:

• Send errors to external services (e.g. Sentry)
• Log to the console in dev
• Alerting / audit trails

Example

export const createServerAction = createClient({
  onError: async (error) => {
    Sentry.captureException(error);
  }
});

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That’s it! Once your client is set up with createClient, you can start defining your actions with shared logic applied automatically.