const CountContext = React.createContext();

const reducer = (state, action) => {
  switch(action.type) {
    case 'increment':
      return {
        count: state.count + 1
      };
    case 'decrement':
      return {
        count: state.count - 1
      };
    default:
      return {
        count: 0
      }
  }
}

const initialState = {
  count: 0,
};

const Child = () => {
  const [state, dispatch] = React.useContext(CountContext);
  return (
    <div>
      Child Count: {state.count}
      <br />
      <button type="button" className="bg-blue-400 p-4 text-white hover:bg-blue-700" onClick={() => dispatch({ type: "decrement" })}>Decrement</button>｜
      <button type="button" className="bg-blue-400 p-4 text-white hover:bg-blue-700" onClick={() => dispatch({ type: "increment" })}>Increment</button>
    </div>
  );
}

const App = () => {
  const countReducer = React.useReducer(reducer, initialState);

  return (
    <div>
      App Count: {countReducer[0].count}
      <br />
      <CountContext.Provider value={countReducer}>
        <Child />
      </CountContext.Provider>
    </div>
  );
}

const root = ReactDOM.createRoot(document.querySelector('#root'));
root.render(<App />);