next-safe-action React Hooks

Import

// All hooks
import { useAction, useOptimisticAction, useStateAction } from "next-safe-action/hooks";

// Backward-compatible re-export (same useStateAction hook)
import { useStateAction } from "next-safe-action/stateful-hooks";

useAction — Quick Start

"use client";

import { useAction } from "next-safe-action/hooks";
import { createUser } from "@/app/actions";

export function CreateUserForm() {
  const { execute, result, status, isExecuting, isPending } = useAction(createUser, {
    onSuccess: ({ data }) => {
      console.log("User created:", data);
    },
    onError: ({ error }) => {
      console.error("Failed:", error.serverError);
    },
  });

  return (
    <form onSubmit={(e) => {
      e.preventDefault();
      const formData = new FormData(e.currentTarget);
      execute({ name: formData.get("name") as string });
    }}>
      <input name="name" required />
      <button type="submit" disabled={isPending}>
        {isPending ? "Creating..." : "Create User"}
      </button>
      {result.serverError && <p className="error">{result.serverError}</p>}
      {result.data && <p className="success">Created: {result.data.id}</p>}
    </form>
  );
}

useOptimisticAction — Quick Start

"use client";

import { useOptimisticAction } from "next-safe-action/hooks";
import { toggleTodo } from "@/app/actions";

export function TodoItem({ todo }: { todo: Todo }) {
  const { execute, optimisticState } = useOptimisticAction(toggleTodo, {
    currentState: todo,
    updateFn: (state, input) => ({
      ...state,
      completed: !state.completed,
    }),
  });

  return (
    <label>
      <input
        type="checkbox"
        checked={optimisticState.completed}
        onChange={() => execute({ todoId: todo.id })}
      />
      {todo.title}
    </label>
  );
}

useStateAction — Quick Start

"use client";

import { useStateAction } from "next-safe-action/hooks";
import { submitFeedback } from "@/app/actions";

export function FeedbackForm() {
  const { formAction, result, isPending, hasSucceeded } = useStateAction(submitFeedback, {
    onSuccess: ({ data }) => {
      console.log("Submitted:", data);
    },
    onError: ({ error }) => {
      console.error("Failed:", error.serverError);
    },
  });

  return (
    <form action={formAction}>
      <input name="rating" type="number" min="1" max="5" required />
      <textarea name="comment" required />
      <button type="submit" disabled={isPending}>
        {isPending ? "Submitting..." : "Submit"}
      </button>
      {result.validationErrors?.comment && (
        <p className="error">{result.validationErrors.comment._errors[0]}</p>
      )}
      {hasSucceeded && <p className="success">Thank you!</p>}
    </form>
  );
}

The server-side action must use .stateAction() (not .action()):

"use server";

import { z } from "zod";
import { actionClient } from "@/lib/safe-action";

export const submitFeedback = actionClient
  .inputSchema(z.object({ rating: z.number().min(1).max(5), comment: z.string() }))
  .stateAction(async ({ parsedInput }, { prevResult }) => {
    // prevResult contains the previous SafeActionResult
    await db.feedback.create({ data: parsedInput });
    return { rating: parsedInput.rating };
  });

Return Value

All hooks (useAction, useOptimisticAction, useStateAction) return:

useOptimisticAction additionally returns: | optimisticState | State | The optimistically-updated state |

useStateAction additionally returns: | formAction | (input) => void | Dispatcher for <form action={formAction}> pattern |

The hook return is itself a discriminated union keyed on status and every has* / is* shorthand (each typed as literal true / false per branch). Narrowing any discriminant narrows result — e.g. inside if (hasSucceeded), result.data is Data (not Data | undefined). See Type narrowing via hook status.

initResult Option

All three hooks accept initResult to seed the hook with a preloaded result (e.g. data fetched on the server): in the opts object for useAction/useStateAction, in the utils object (alongside currentState/updateFn) for useOptimisticAction. The value is captured once at mount (like React's useActionState initial state): later changes to the option are ignored, and reset() restores the mount value. The seeded shape precisely types the idle branch's result. See initResult in depth.

Supporting Docs

• execute vs executeAsync, result handling
• useStateAction in depth (decision table, formAction)
• Optimistic updates with useOptimisticAction
• Status lifecycle and all callbacks
• throwOnNavigation flag

Anti-Patterns

// BAD: Using executeAsync without try/catch when navigation errors are possible
const handleClick = async () => {
  const result = await executeAsync({ id }); // Throws on redirect!
  showToast(result.data);
};

// GOOD: Wrap executeAsync in try/catch
const handleClick = async () => {
  try {
    const result = await executeAsync({ id });
    showToast(result.data);
  } catch (e) {
    // Handle non-navigation errors here if needed, then re-throw
    // Navigation errors must propagate to Next.js
    throw e;
  }
};

// BAD: Using .action() with useStateAction — type error
const myAction = actionClient.inputSchema(schema).action(async ({ parsedInput }) => { ... });
useStateAction(myAction); // TypeScript error!

// GOOD: Use .stateAction() for useStateAction
const myAction = actionClient.inputSchema(schema).stateAction(async ({ parsedInput }, { prevResult }) => { ... });
useStateAction(myAction); // Works!