[Mistakes]: Server Functions examples use incompatible action signatures

Summary

The updateName Server Function is defined as updateName(name), but the page later uses it as a direct form action and with useActionState. These usages pass different arguments, so the examples cannot work with the shown function.

Page

https://react.dev/reference/rsc/server-functions

Details

The page defines:

export async function updateName(name) {
  if (!name) {
    return {error: 'Name is required'};
  }
  await db.users.updateName(name);
}

There are several inconsistencies/mistakes:

• In “Server Functions with Actions”, the input does not update the name state, so updateName(name) always receives ''.

• On success, updateName returns undefined, but the client destructures {error} from its result.

• When passed to <form action={updateName}>, React calls updateName with FormData, not a string.

• When passed to useActionState, React calls it with (previousState, FormData), and it must consistently return the next state.

The examples should define a Server Function with the correct parameters and return value for each usage.

https://react.dev/reference/rsc/server-functions の Server Functions リファレンスページから始め、「Server Functions with Actions」、直接のフォームアクション、useActionState の使用における updateName の例を比較します。各例のパラメーターと戻り値が、FormData 引数と前の状態の引数を含め、React がそれを呼び出す方法と一致すれば完了です。