next-safe-action TanStack Query Adapter

Install

npm install @next-safe-action/adapter-tanstack-query @tanstack/react-query

Import

import {
  mutationOptions,
  ActionMutationError,
  isActionMutationError,
  hasServerError,
  hasValidationErrors,
} from "@next-safe-action/adapter-tanstack-query";

Quick Start

"use client";

import { useMutation } from "@tanstack/react-query";
import { mutationOptions } from "@next-safe-action/adapter-tanstack-query";
import { createUser } from "@/app/actions";

export function CreateUserForm() {
  const { mutate, isPending, isError, error, data } = useMutation(
    mutationOptions(createUser, {
      onSuccess: (data) => {
        toast.success(`Created ${data.name}`);
      },
    })
  );

  return (
    <form onSubmit={(e) => {
      e.preventDefault();
      const fd = new FormData(e.currentTarget);
      mutate({ name: fd.get("name") as string, email: fd.get("email") as string });
    }}>
      <input name="name" required />
      <input name="email" type="email" required />
      <button type="submit" disabled={isPending}>
        {isPending ? "Creating..." : "Create User"}
      </button>
      {isError && <p className="text-red-500">{error.message}</p>}
      {data && <p>Created: {data.name}</p>}
    </form>
  );
}

How It Works

mutationOptions() creates a complete UseMutationOptions object that bridges next-safe-action's result envelope to TanStack Query's error model:

1. Calls the safe action with input provided to mutate() / mutateAsync()
2. Inspects the result envelope for serverError or validationErrors
3. Throws ActionMutationError if either is present (a client-side error class, instanceof works)
4. Returns data directly as TanStack Query's TData on success
5. Handles navigation errors (redirect(), notFound(), etc.) by composing throwOnError to always re-throw them during React's render phase

When to Use Which

Scenario	Recommendation
New Next.js project without TanStack Query	Built-in hooks
Simple form submissions and button actions	Built-in hooks
Instant optimistic UI via React's useOptimistic	Built-in hooks (useOptimisticAction)
Zero additional dependencies	Built-in hooks
Already using TanStack Query for data fetching	Adapter
Already using tRPC + TanStack Query	Adapter
Need automatic retries with backoff	Adapter
Need to invalidate client query cache after mutations	Adapter
Want TanStack Query DevTools for mutations	Adapter
Need offline mutation persistence	Adapter

Feature Comparison

Feature	Built-in hooks	Adapter
React Transitions	Yes, actions run inside startTransition	No
Optimistic updates	useOptimisticAction via React's useOptimistic	Manual via onMutate + query cache
Automatic retries	No	Yes, retry option with backoff
Server cache invalidation	Yes, revalidatePath() / revalidateTag()	Yes, same Next.js APIs
Client query cache invalidation	No (not applicable)	Yes, queryClient.invalidateQueries()
DevTools	No	Yes, TanStack Query DevTools
Error model	Result envelope (result.serverError, result.validationErrors)	Thrown ActionMutationError with type guards
Offline mutation persistence	No	Yes, paused mutations via dehydrate/hydrate
Async execution	executeAsync() returns Promise<Result>	mutateAsync() returns Promise<Data>
Status tracking	status string + shorthand booleans	Boolean flags (isPending, isError, isSuccess)
Extra dependencies	None (React only)	@tanstack/react-query

General guidance: Prefer built-in hooks for most Next.js apps. They require no extra dependencies and integrate with React's concurrent rendering. Prefer the adapter when TanStack Query is already part of your stack, especially for cache invalidation, retries, DevTools, and offline support.

Why Mutations Only

This adapter provides only mutationOptions(). There is no queryOptions(), by design:

• Server Actions use POST only, not suitable for GET-based queries
• Server Actions are queued per client, creating request waterfalls
• POST requests bypass browser cache, ETag, and conditional requests
• No stable resource identity for TanStack Query deduplication

For data fetching: use Server Components (server-side), Route Handlers + useQuery (client-side), or tRPC (full-stack type-safe).

Entry Points

Entry point	Exports	Environment
@next-safe-action/adapter-tanstack-query	mutationOptions, ActionMutationError, isActionMutationError, hasServerError, hasValidationErrors, types	Client

Important Constraints

Only works with non-throwing actions. Do NOT use throwValidationErrors: true or throwServerError: true with actions passed to mutationOptions(). The adapter inspects the result envelope for errors. If errors are thrown instead of returned, the adapter cannot extract structured error data, and you lose type-safe error handling. TypeScript enforces this via NonThrowingActionConstraint.

Supporting Docs

• Mutation patterns, error handling, and optimistic updates

Anti-Patterns

// BAD: Using throwValidationErrors with adapter — errors bypass the result envelope
const client = createSafeActionClient({ throwValidationErrors: true });
const action = client.inputSchema(schema).action(async ({ parsedInput }) => { ... });
mutationOptions(action); // TypeScript error! NonThrowingActionConstraint not met

// BAD: Using mutationOptions for data fetching — server actions are POST-only
const { data } = useQuery(mutationOptions(fetchUsers)); // Wrong! Use Route Handler + useQuery

// BAD: Manually calling the action inside mutationFn
useMutation({
  mutationFn: async (input) => {
    const result = await myAction(input); // Loses error bridging, navigation handling
    return result.data;
  },
});

// GOOD: Let mutationOptions handle the bridging
useMutation(mutationOptions(myAction));