Fix the reducer that never returns state — find the bug

function reducer(state, action) {
  if (action.type === "add") return state + 1
  return state
}

function App() {
  const [count, dispatch] = React.useReducer(reducer, 0)
  return (
    <div>
      <p id="value">{count}</p>
      <button id="inc" onClick={() => dispatch({ type: "inc" })}>add</button>
    </div>
  )
}
const root = ReactDOM.createRoot(document.getElementById("root"))
root.render(<App />)